#include<bits/stdc++.h>
using namespace std;
#define rep(i,0,n) for(int i=0;i<n;i++)
int main()
{
  int n;
  string s;
  cin>>n>>s;
  int l=(int)s.size();
  if(l>n)
  {
    rep(i,0,n)
      cout<<s[i];
    rep(i,0,l-n)
      cout<<'.';
  }
  else
    cout<<s;
}