import java.util.Scanner;
class Main
{
	public static void main(String args[])
	{
		Scanner sc=new Scanner(System.in);
        String c0=sc.next();
        char[] c1=c0.toCharArray();

        char alphabet[]=new char[26];
        char c='a';
        for(int i=0; i<26; i++){
            alphabet[i]=c++;
        }
        for(int j=0; j<26; j++){
            if(c1[0]==alphabet[j]){
                System.out.println(alphabet[j+1]);
                break;
            }
        }
        sc.close();
    }
}
/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