const main = input => {
  const inputs = input.split('\n')
  const K = parseInt(inputs[0].trim())
  const S = inputs[1].trim()

  if (S.length <= K) {
    console.log(S)
  } else {
    console.log(S.substr(0, K) + '...')
  }
}
// 標準入力
main(require("fs").readFileSync("/dev/stdin", "utf8"));
