process.stdin.resume()
process.stdin.setEncoding('utf8')
console.log('What\'s your age ? ')
process.stdin.on('data', (age) => {
 if (isNaN(age) || age > 99){
   console.log('You must enter a NUMBER under 99. ');
   process.exit()
 } else {
   const birthYear = new Date().getFullYear() - age;
   console.log('You were born in '+ birthYear);
   process.exit()
 }
})