function main(input){
  const K = parseInt(input.split('\n')[0]);
  const S = input.split('\n')[1];
  if (S.length <= K) {
  	console.log(S);
  }else{
    console.log(S.substr(0,K)+"...");
  }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));