#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using p = pair<int, int>;
int main() {
  int k;
  string s;
  cin >> k >> s;
  if (int(s.size()) <= k)
    cout << s << endl;
  else
    cout << s.erase(k - 1) + "..." << endl;
}
