#include <iostream>
#include <algorithm>
#include <cmath>
#include <string>
#define ll long long
using namespace std;

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

    int n, cv=1; string x; cin >> n;
    while (n--)
    {
        cin >> x;
        if (cv % 3 == 0 && cv % 5 == 0)
        {
            if (x != "BUMM")
            {
                cout << cv << endl;
                return 0;
            }
        }
        else if (cv % 3 == 0)
        {
            if (x != "BIMM")
            {
                cout << cv << endl;
                return 0;
            }
        }
        else if (cv % 5 == 0)
        {
            if (x != "BAMM")
            {
                cout << cv << endl;
                return 0;
            }
        }
        else
        {
            if (x != "SZAM")
            {
                cout << cv << endl;
                return 0;
            }
        }
        cv++;
    }
    

    return 0;
}