using System;
namespace Test
{
class Program
static char f(string s)
int i=0,j=0;for(;i<s.Length;)j+=s[i++]-97;return(char)(97+j%26);
}
static void Main()
Console.WriteLine(f("helloworld")); // k
Console.WriteLine(f("abcdef")); // p
Console.WriteLine(f("codegolf")); // h
Console.WriteLine(f("stackexchange")); // e
Console.WriteLine(f("aaaaa")); // a