"use strict";
// import bigInt from 'big-integer'

const Main = input => {
  input = input.trim()
  const a = 'abcdefghijklmnopqrstuvwxyz'
  const i = a.indexOf(input) + 1

  console.log(a[i]);
};

Main(require("fs").readFileSync("/dev/stdin", "utf8"));
