using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        string s = "GeekssForGeeks";

        string x = "For";

        Console.Write(FindSubStr(s,x));

    }

    public static int FindSubStr(string s, string x)

    {

        int i=0;

        int j=0;

        while(i < s.Length- 1)

        {

            if(s[i] == x[j])

            {

                j++;

                if(j == x.Length-1)

                    return i-j+1;

            }

            i++;

        }

        return -1;

    }

}