function Main(input){
  input = input.trim().split('\n');
  var K = input[0];
  var S = input[1];
  var ans = '';
  if (S.length <= K){
    ans = S;
  }else{
    ans = S.slice(0,K) + '...';
  }
  console.log(ans);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));