using System;

namespace bimmbamm
{
    class Program
    {
        static void Main()
        {
            int len = int.Parse(Console.ReadLine());
            string be = "";
            int breaks = 0;

            for (int i = 1; i <= len; i++)
            {
                be = Console.ReadLine();

                if (i % 15 == 0 && be != "BUMM")
                {
                    breaks = i;
                    break; // Exit the loop once a break condition is met
                }
                else if (i % 3 == 0 && i % 5 != 0 && be != "BIMM")
                {
                    breaks = i;
                    break;
                }
                else if (i % 5 == 0 && i % 3 != 0 && be != "BAMM")
                {
                    breaks = i;
                    break;
                }
                else if (i % 3 != 0 && i % 5 != 0 && be != "SZAM")
                {
                    breaks = i;
                    break;
                }
            }

            Console.WriteLine(breaks);
            Console.ReadKey();
        }
    }
}