// Author:: MOHAMMAD FAISAL
"use strict";

const main = (input) =>{
  	
  const arr = input.trim().split("\n");
  let n = parseInt(arr[0]);
  let s = arr[1];
  
  
  if(s.length <= n)
    console.log(s);
  else{
    let start = s.substr(0,n);
    console.log(start+"...");
  }
};

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