import java.util.Scanner;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);

    String alphabet = "abcdefghijklmnopqrstuvwxyz";

    String inputString = sc.next();
    char inputChar = inputString.charAt(0);

    for(int i = 0; i < alphabet.length(); i++){
      if( alphabet.charAt(i) == inputChar ){
        System.out.println( alphabet.charAt(i+1) );
        break;
      }
    }
  }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz