'use strict'
function main(input) {
  input = input.trim().split('\n')
  const num = input[2]
  let text = input[1]
  const char = new RegExp(`[^${text[num-1]}]`, 'g')
  text = text.replace(char, '*');
  console.log(text)
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));
