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

#define int long long

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int jo[1100] = {0};
    for(int i = 1; i < 1100; i++) {
        if (i % 15 == 0) {
            jo[i] = 1;
        } else if (i % 3 == 0) {
            jo[i] = 2;
        } else if (i % 5 == 0) {
            jo[i] = 3;
        }
    }

    int n;
    cin >> n;

    for(int i = 1; i <= n; i++) {
        string x;
        cin >> x;
        int val = 0;
        if(x == "BIMM") {
            val = 2;
        } else if (x == "BAMM") {
            val = 3;
        } else if (x == "BUMM") {
            val = 1;
        }

        if (jo[i] != val) {
            cout << i << '\n';
            return 0;
        }
    }
    cout << 0 << '\n';
}