process.stdin.resume()
process.stdin.setEncoding('utf8')

console.log('How old are you ? ')
process.stdin.on('data', (check) => {

    if ((isNaN(check)) || (check > 99 )) {
        console.log('please enter a number under 99');
    }
    else {
        console.log("You were born in " + (2019 - check));
        process.exit();
    }

}
);