const main = arg => {
  const input = arg.trim().split('\n');
  const k = Number(input[0]);
  const s = input[1];

  if (s.length <= k) {
    console.log(s);
  } else {
    console.log(`${s.slice(0, k)}...`);
  }
};

main(require('fs').readFileSync('/dev/stdin', 'utf8'));
