#include <bits/stdc++.h>

using namespace std;

void print(vector<pair<int, int>> v)
{
    cout << " ---> ";
    for (auto &it : v)
    {
        cout << "(" << it.first << ", " << it.second << ") ";
    }
    cout << "\n";
}

const int N = 20 + 7;
int n;
long double radr;
bool insidecircle[N][N];
bool intersectcircle[N][N];
bool potscot[N][N];
int maxhas;
bool okplaceborder[N][N];
vector<pair<int, vector<pair<int, int>>>> dp[N];
vector<int> papa[N];

vector<pair<int, int>> nw;
vector<bool> keep;

bool inscells(vector<pair<int, int>> current, int row, int mask)
{
    nw.clear();
    keep.clear();
    keep.resize((int) current.size(), 1);


    for (int col = 0; col <= n; col++)
    {
        if (mask & (1 << col))
        {
            // cout << " : " << row << " and " << col << "\n";
            // if (row == 5 && col == 2) exit(0);
            nw.push_back({row, col});
            for (int i = 0; i < (int) current.size(); i++)
            {
                auto &[r, c] = current[i];
                assert(r < row);
                if (intersectcircle[row - r][abs(c - col)])
                {
                    return 0;
                }
                if (potscot[row - r][abs(c - col)]) 
                {
                    keep[i] = 0;
                }
            }
        }
    }
    for (int i = 0; i < (int) current.size(); i++)
    {
        auto &[r, c] = current[i];
        if (r + radr <= row + 1 - radr) continue;
       // if (keep[i]) ////////////////////////////////////////////////////////////////////////////////////////////
        {
            nw.push_back({r, c});
        }
    }
    sort(nw.begin(), nw.end());

    return 1;
}

int main()
{
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> radr;
    if (radr <= 0.5)
    {
        cout << (n - 1) * (n - 1) << "\n";
        for (int i = 1; i <= n - 1; i++)
        {
            for (int j = 1; j <= n - 1; j++)
            {
                cout << i << " " << j << "\n";
            }
        }
        return 0;
    }
    for (int x = 0; x <= n; x++)
    {
        for (int y = 0; y <= n; y++)
        {
            insidecircle[x][y] = (x * x + y * y <= radr * radr);
            if (insidecircle[x][y]) maxhas = x;
            
            intersectcircle[x][y] = (x * x + y * y < 4 * radr * radr);
        }
    }



    for (int x = 0; x <= n; x++)
    {
        for (int y = 0; y <= n; y++)
        {
            potscot[x][y] = 1;
            for (int r = x; r <= n; r++)
            {
                for (int c = 0; c <= n; c++)
                {
                    if (insidecircle[r][c] && !insidecircle[abs(x - r)][abs(y - c)])
                    {
                        potscot[x][y] = 0;
                    }
                }
            }
        }
    }
    for (int r = 1; r <= n; r++)
    {
        for (int c = 1; c <= n; c++)
        {
            okplaceborder[r][c] = (r - radr >= 0 && c - radr >= 0 && r + radr <= n && c + radr <= n);
        }
    }

    vector<int> validmasks;
    for (int mask = 0; mask < (1 << (n + 1)); mask++)
    {
        bool valid = 1;
        vector<int> who;
        for (int c = 0; c <= n; c++) if (mask & (1 << c)) who.push_back(c);
        for (auto &i : who)
        {
            valid &= (i + radr <= n && i - radr >= 0);
        }

        for (int i = 1; i < (int) who.size(); i++)
        {
            valid &= (who[i - 1] + radr <= who[i] - radr);
        }
        if (valid) validmasks.push_back(mask);
    }
    // for (auto &mask : validmasks)
    // {
    //     for (int c = 0; c <= n; c++)
    //     {
    //         cout << !!(mask & (1 << c));
    //     }
    //     cout << "\n";
    // }
    // return 0;

    if (0)
     for (int r = 0; r <= n; r++)
     {
       for (int c = 0; c <= n; c++)
         {
             cout << okplaceborder[r][c] << " "; 
        }
         cout << "\n";
     }

    dp[0].push_back({0, {}});
    for (int r = 0; r < n; r++)
    {
        // go from r to r + 1
        map<vector<pair<int, int>>, pair<int, int>> mp;

        for (int i = 0; i < (int) dp[r].size(); i++)
        // for (auto &[coef, cells] : dp[r])
        {
            auto &[coef, cells] = dp[r][i];
            for (auto &mask : validmasks)
            {
                bool ok = 1;
                int cntbits = 0;
                for (int c = 0; c <= n; c++)
                {
                    if (mask & (1 << c))
                    {
                        ok &= okplaceborder[r + 1][c];
                        cntbits++;
                    }
                }
                if (!ok) continue;
                ok &= inscells(cells, r + 1, mask);
                if (!ok) continue;
                if (mp.count(nw) && coef + cntbits <= mp[nw].first) continue;
                mp[nw].first = coef + cntbits;
                mp[nw].second = i;
            }
        }
        for (auto &it : mp)
        {
            dp[r + 1].push_back({it.second.first, it.first});
            papa[r + 1].push_back(it.second.second);
        }
    }
    int sol = -1, cr = -1;
    for (int i = 0; i < (int) dp[n].size(); i++)
    {
        auto &it = dp[n][i];
        if (it.first > sol)
        {
            sol = it.first;
            cr = i;
        }
    }
    if (0)
    for (int r = 0; r <= n; r++)
    {
        for (auto &it : dp[r])
        {
             cout << r << ", " << it.first;
            print(it.second);
        }
         cout << "\n\n";
    }
    // cout << "sol = " << sol << "\n";
    set<pair<int, int>> all;
    for (int i = n; i >= 1; i--)
    {
        assert(0 <= cr && cr < (int) dp[i].size());
        assert((int) dp[i].size() == (int) papa[i].size());
        for (auto &it : dp[i][cr].second)
        {
            all.insert(it);
        }
        cr = papa[i][cr];
    }
    assert(cr == 0);
    assert((int) all.size() == sol);
    cout << sol << "\n";
    for (auto &it : all)
    {
        cout << it.first << " " << it.second << "\n";
    }
    return 0;

    // cout << " : " << maxhas << "\n";


    return 0;
}