const input = require("fs").readFileSync("/dev/stdin", "utf8")
let cin = input.split(/ |\n/), cid = 0
const next = () => cin[cid++]
const nexts = (n) => cin.slice(cid, cid+=n).map(i=>parseInt(i))

const alpha = next()

function isUpperCase(str) {
    return str === str.toUpperCase();
}

isUpperCase(alpha) ? console.log('A') : console.log('a')
