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****.

no yes no no no yes yes no yes yes yes yes yes yes no yes yes yes yes yes yes yes yes yes yes yes no no no yes yes yes yes no no yes yes yes yes yes no yes yes no no no yes yes no yes yes no no no yes yes yes yes no yes yes yes no
#include <bits/stdc++.h>
int main() {
  int num = 0;
  std::cin >> num;
  std::string sequence = "";
  std::cin >> sequence;
  int start = -1;
  int second = -1;
  for (int i = 0; i < sequence.length(); i++) {
    if (start == -1 && sequence[i] == '*') {
      start = i;
    }
    if (second == -1 && sequence[i] == '*') {
      start = i;
      break;
    }
  }
  bool yes = true;
  if (start == -1 && second == -1) {
    yes = false;
  } else {
    for (int jumpDist = 1; jumpDist < num / 4; jumpDist++) {
      yes = true;
      for (int jumpCount = 1; jumpCount < 5; jumpCount++) {
        if (start + (jumpDist * jumpCount) >= sequence.length() &&
            jumpCount < 4)
          yes = false;
        if (start + (jumpDist * jumpCount) >= sequence.length()) break;
        if (sequence[start + (jumpDist * jumpCount)] != '*') yes = false;
        break;
      }
      if (yes == true) break;
    }
  }
  if (yes)
    std::cout << "yes";
  else
    std::cout << "no";
  return 0;
}
