import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner scan = new java.util.Scanner(System.in);
        String s = scan.next();
        char c = s.charAt(0);
        char out;
        switch(c){
            case 'a':
                out = 'b';
                System.out.println(out);
                break;
            case 'b':
                out = 'c';
                System.out.println(out);
                break;
            case 'c':
                out = 'd';
                System.out.println(out);
                break;
            case 'd':
                out = 'e';
                System.out.println(out);
                break;
            case 'e':
                out = 'f';
                System.out.println(out);
                break;
            case 'f':
                out = 'g';
                System.out.println(out);
                break;
            case 'g':
                out = 'h';
                System.out.println(out);
                break;
            case 'h':
                out = 'i';
                System.out.println(out);
                break;
            case 'j':
                out = 'k';
                System.out.println(out);
                break;
            case 'k':
                out = 'l';
                System.out.println(out);
                break;
            case 'l':
                out = 'm';
                System.out.println(out);
                break;
            case 'm':
                out = 'n';
                System.out.println(out);
                break;
            case 'n':
                out = 'o';
                System.out.println(out);
                break;
            case 'o':
                out = 'p';
                System.out.println(out);
                break;
            case 'p':
                out = 'q';
                System.out.println(out);
                break;
            case 'q':
                out = 'r';
                System.out.println(out);
                break;
            case 'r':
                out = 's';
                System.out.println(out);
                break;
            case 's':
                out = 't';
                System.out.println(out);
                break;
            case 't':
                out = 'u';
                System.out.println(out);
                break;
            case 'u':
                out = 'v';
                System.out.println(out);
                break;
            case 'v':
                out = 'w';
                System.out.println(out);
                break;
            case 'w':
                out = 'x';
                System.out.println(out);
                break;
            case 'x':
                out = 'y';
                System.out.println(out);
                break;
            case 'y':
                out = 'z';
                System.out.println(out);
                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