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

#define ll long long
#define pb push_back
#define mp make_pair
#define fi first
#define se second

string jo(int x) {
    int res = 0;
    if(x % 3 == 0 && x % 5 == 0) return "BUMM";
    if(x % 3 == 0) return "BIMM";
    if(x % 5 == 0) return "BAMM";
    return "SZAM";
}

void solve() {
    int n;
    cin >> n;
    vector<string> v(1 + n, "");
    for(int i = 1; i <= n; i++) {
        cin >> v[i];
        if(v[i] != jo(i)) {
            cout << i << "\n";
            return;
        }
    }
    cout << "0\n";
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    // int T = 1; cin >> T; while(T--)// !!!!!
    solve();
    return 0;
}