import java.io.IOException;

public class Main {
    public static void main(String[] args) throws IOException {
        char c = (char) System.in.read();
        int b=0;
        if( c>=97 && c<122){
            b = c + 1;
        }
        else {
            System.out.println("Not allowed");
        }
        c =(char)b;
        System.out.println(c);
    }
}
/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