import java.util.Scanner;

class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    String s = sc.next();
    char[] c = s.toCharArray();
    
    String t = "abcdefghijklmnopqrstuvwxyz";
    char[] al = t.toCharArray();
    
    for(int i = 0; i < t.length(); i++){
      if(c[0] == al[i]){
        System.out.println(al[i+1]);
      }
    }
    
  }
}

/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