var main = standardInput => {
  var input = standardInput.split('\n').map(function(v){
    return v
  });
  var N = input[0];
  var S = input[1];
  var K = parseInt(input[2],10);

  var letter = "[^" + S[K-1] + "]";

  console.log(S.replace(new RegExp(letter,"g"),"*"));

};
main(require("fs").readFileSync("/dev/stdin", "UTF-8"));