"use strict"
function main(arg) {
    var src = arg.trim().split("\n")[0]
    var data = 'abcdefghijklmnopqrstuvwxyz'.split('')
    var i = 0
    for (i = 0; i < data.length; i++) {
        if (data[i] === src) {
            break
        }
    }
    console.log(data[i+1])
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));