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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>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
int main() {
  string s;
  int n;
  while (~scanf("%d", &n)) {
    cin >> s;
    int len = s.size();
    vector<int> vec;
    int a[1000], idx = 0;
    for (int i = 0; i < len; i++) {
      if (s[i] == '*') {
        vec.push_back(i + 1);
        a[idx++] = i + 1;
      }
    }
    bool flag = 0;
    for (int i = 0; i < vec.size(); i++) {
      int t = vec[i];
      for (int j = 1; j <= 21; j++) {
        bool ans = 0;
        for (int k = 0; k <= 4; k++) {
          if (vec[i] + k * j <= len && s[vec[i] + k * j - 1] != '*')
            ans = 1;
          else if (vec[i] + k * j > len)
            ans = 1;
        }
        if (ans == 0) {
          flag = 1;
          break;
        }
      }
      if (flag) break;
    }
    if (flag)
      printf("yes\n");
    else
      printf("no\n");
  }
  return 0;
}
