"use strict";
    
const main = arg => {
    arg = arg.trim().split("\n");
    const C = arg[0];
    const alphabets = "abcdefghijklmnopqrstuvwxyz".split("");
    
    const temp = alphabets.indexOf(C);
    
    console.log(alphabets[temp + 1]);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));