// ConsoleApplication1.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
//#include <fstream>
#include <string>
#include <vector>
//#include <cstdlib>
using namespace std;

string s;

int i, n;
bool db;
//vector<string>x;

int main()
{
    cin >> n;
    for (i = 1; i <= n; ++i)
    {
        cin >> s;
        if (i % 3 == 0 && i % 5 == 0)
        {
            if (s[1] != 'U')
            {
                cout << i;
                db = true;
                break;
            }
        }
        else if (i % 3 == 0)
        {
            if (s[1] != 'I')
            {
                cout << i;
                db = true;
                break;
            }
        }
        else if (i % 5 == 0)
        {
            if (s[1] != 'A')
            {
                cout << i;
                db = true;
                break;
            }
        }
        else if (s[0] != 'S')
        {
            cout << i;
            db = true;
            break;
        }
    }
    //system("pause");
    if (db == false) cout << 0;
    return 0;
}


// Run program: Ctrl + F5 or Debug > Start Without Debugging menu
// Debug program: F5 or Debug > Start Debugging menu

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file