function Main(input){
  
  var str = input.trim().split("\n");
  var n = parseInt(str[0],10);
  var s = str[1];
  var k = parseInt(str[2],10);

  //console.log(s);
  
  var target = s.substr(k-1,1);
  
  regexp = new RegExp("[^"+target+"]","g");
  
  var news = s.replace(regexp,"*");
  
  console.log(news)
  

  
  
  
}//function end
 
Main(require("fs").readFileSync("/dev/stdin", "utf8"));