#include <bits/stdc++.h>
using namespace std;

#define tsolve int t; cin >> t; while (t--) solve
#define all(x) ::begin(x), ::end(x)
#define sz(x) (ll)::size(x)

using ll = long long;
using ld = long double;

ll n;
vector<char> c, p;

bool solve_part(vector<string>& res) {
    ll curc = n;
    for (ll i = 0; i < n; ++i) {
        if (c[i] == '-' && p[i] != '-') {
            curc = i;
            break;
        }
    }

    if (curc == n) {
        return false;
    }


    ll curp = p[curc];
    p[curc] = '-';
    res.push_back("DRIVE " + to_string(curc + 1));


    bool t = true;
    while (t) {
        t = false;
        for (ll i = 0; i < n; ++i) {
            if (c[i] == curp && p[i] != curp && p[i] != '-') {
                res.push_back("PICKUP");
                res.push_back("DRIVE " + to_string(i + 1));
                res.push_back("DROPOFF");
                curp = p[i];
                p[i] = c[i];

                t = true;
                break;
            }
        }

        if (t) continue;

        for (ll i = 0; i < n; ++i) {
            if (c[i] == curp && p[i] == '-') {
                res.push_back("PICKUP");
                res.push_back("DRIVE " + to_string(i + 1));
                res.push_back("DROPOFF");
                curp = p[i];
                p[i] = c[i];

                return true;
            }
        }
    }

    return true;
}

void solve() {
    cin >> n;
    c.resize(n);
    for (char& x : c) cin >> x;
    p.resize(n);
    for (char& x : p) cin >> x;

    vector<string> res;
    while (solve_part(res));

    cout << ssize(res) << '\n';
    for (string x : res) cout << x << '\n';
}

int main() {
    cin.tie(0)->sync_with_stdio(false);
    cout << setprecision(16);
    solve();
}