
function main(lines) {
    const a = lines[0].charAt(0)

    if ('a'.charAt(0) <= a && a <= 'z'.charAt(0))
	    console.log('a')
    if ('A'.charAt(0) <= a && a <= 'Z'.charAt(0))
	    console.log('A')
}


main(require("fs").readFileSync("/dev/stdin", "utf8").split("\n"))
