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

using ll = long long;
using ld = long double;
using pii = pair<ll, ll>;
using vi = vector<ll>;
using vvi = vector<vi>;
#define rep(i, a, b) for(ll i = (a); i < (b); i++)
#define all(x) begin(x),end(x)
#define sz(x) (int)(x).size()

void solve() {
    ll n;
    string c, p;
    cin >> n >> c >> p;
    vvi types(6);
    rep(i,0,n) {
#define gah(c1, c2, t0) if (c[i] == c1 && p[i] == c2) types[t0].push_back(i + 1);
        gah('M', 'C', 0)
        gah('C', 'M', 1)
        gah('-', 'C', 2)
        gah('-', 'M', 3)
        gah('M', '-', 4)
        gah('C', '-', 5)
    }
    vector<string> total;
    rep(i, 0, 2) {
        while (!empty(types[4 + i])) {
            ll z = types[4 + i].back();
            types[4 + i].pop_back();
            vector<vector<string>> ops;
            ops.push_back({"DRIVE " + to_string(z), "DROPOFF"});
            ll nx = !i;
            while (!empty(types[nx])) {
                auto zz = types[nx].back();
                types[nx].pop_back();
                ops.push_back({"DRIVE " + to_string(zz), "DROPOFF", "PICKUP"});
                nx ^= 1;
            }
            nx = 2 + nx;
            ops.push_back({"DRIVE " + to_string(types[nx].back()), "PICKUP"});
            types[nx].pop_back();
            reverse(all(ops));
            for (auto& x : ops) for (auto& y : x)
                total.push_back(y);
        }
    }
    ll first = sz(types[0]) > sz(types[1]) ? 0 : sz(types[0]) < sz(types[1]) ? 1 : empty(types[2]) ? 1 : 0; // sus
    for (ll i : {first, 1 - first}) {
        while (!empty(types[i])) {
            ll z = types[i].back();
            types[i].pop_back();
            vector<vector<string>> ops;
            ops.push_back({"DRIVE " + to_string(z), "DROPOFF"});


            ll nx = !i;
            while (!empty(types[nx])) {
                auto zz = types[nx].back();
                types[nx].pop_back();
                ops.push_back({"DRIVE " + to_string(zz), "DROPOFF", "PICKUP"});
                nx ^= 1;
            }
            nx = 2 + nx;
            ops.push_back({"DRIVE " + to_string(types[nx].back()), "PICKUP"});
            types[nx].pop_back();
            reverse(all(ops));
            for (auto& x : ops) for (auto& y : x)
                    total.push_back(y);
        }
    }
    cout << ssize(total) << "\n";
    for (auto& x : total)
        cout << x << '\n';
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);

    //ll t; cin >> t; while(t--)
        solve();
}