// Bimm, bamm, bumm.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>

using namespace std;

long long i, n;
string s;

int main()
{
	cin >> n;

	for (i = 1; i <= n; ++i)
	{
		cin >> s;
		if (i % 3 == 0 && i % 5 == 0 && s[1] != 'U')
		{
			cout << i;
			return 0;
		}
		if (i%3==0 && s[1]!='I')
		{
			cout << i;
			return 0;
		}
		if (i%5==0 && s[1]!='A')
		{
			cout << i;
			return 0;
		}
		if ((i % 3 != 0 || i % 5 == 0) && s[1] != 'Z')
		{
			cout << i;
			return 0;
		}
	}

	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