using System;
using System.Linq;

namespace NthChar
{
    public class StartUp
    {
        public static void Main()
        {
            string input = Console.ReadLine();
            string[] data = Console.ReadLine().Split();
            char charToFind = data[0][0];
            int occurrences = int.Parse(data[1]);

            var result = input.Select((c, i) => new { Char = c, Index = i })
                   .Where(item => item.Char == charToFind)
                   .Skip(occurrences - 1)
                   .FirstOrDefault();

            Console.WriteLine(result?.Index.ToString()?? "Find the letter yourself!");

        }

    }
}