Problem:
Score : 100 points

Problem Statement

Given is a lowercase English letter C that is not z. Print the letter that follows C in alphabetical order.

Constraints

C is a lowercase English letter that is not z.

Input

Input is given from Standard Input in the following format:

C

Output

Print the letter that follows C in alphabetical order.

Sample Input 1

a

Sample Output 1

b

a is followed by b.

Sample Input 2

y

Sample Output 2

z

y is followed by z.

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Diagnostics;

namespace atcode
{
    class Program
    {

        static void Main(string[] args)
        {

            string charString = "abcdefghijklmnopqrstuvwxy";
            
            string inputS = Console.ReadLine().Trim();

            if(inputS == "z") { return; }

            int inputindex = charString.IndexOf(inputS);
            if(inputindex < 0) { return;  }

            int nextIndex = inputindex + 1;

            string nextShar = charString.Substring(nextIndex, 1);

            Console.WriteLine(nextShar);
//            Debug.WriteLine(nextShar);
        }
    }
}