import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    String t = scan.next();
    String g = "abcdefghijklmnopqrstuvwxyza";
    for (int i=0;i<g.length();i++){
      if (g.charAt(i) == t.charAt(0)){
        System.out.println(g.charAt(i+1));
        return;
      }
    }
  }
}

/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