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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;
void err(istream_iterator<string> it) {}
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << endl;
  err(++it, args...);
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  string str;
  cin >> str;
  bool good = false;
  for (long long int i = (1); i <= (long long int)(30); ++i) {
    for (long long int j = (0); j <= (long long int)(n); ++j) {
      if (j + (i * 4) >= n)
        break;
      else if (str[j] == '*' && str[j + i] == '*' && str[j + (2 * i)] == '*' &&
               str[j + (3 * i)] == '*' && str[j + (4 * i)] == '*') {
        good = true;
      }
    }
  }
  if (good)
    cout << "yes";
  else
    cout << "no";
}
