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 5
****.

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;
template <typename T>
inline T sqr(const T &x) {
  return x * x;
}
const int N_MAX = 20000;
const int SUP_I = (int)1e+9;
const unsigned long long int SUP_LL = (unsigned long long int)1e+16;
const double EPS = 1e-6;
int main() {
  int n;
  cin >> n;
  char c;
  vector<int> a;
  for (int i = 0; i < n; i++) {
    cin >> c;
    if (c == '*') a.push_back(i);
  }
  bool f = false;
  if (a.size() >= 5) {
    for (int i1 = 0; i1 < a.size() - 4 && !f; i1++) {
      for (int i2 = i1 + 1; i2 < a.size() - 3 && !f; i2++) {
        for (int i3 = i2 + 1; i3 < a.size() - 2 && !f; i3++) {
          for (int i4 = i3 + 1; i4 < a.size() - 1 && !f; i4++) {
            for (int i5 = i4 + 1; i5 < a.size() && !f; i5++) {
              int delux = a[i2] - a[i1];
              f = (a[i5] - a[i4] == delux && a[i4] - a[i3] == delux &&
                   a[i3] - a[i2] == delux);
            }
          }
        }
      }
    }
  }
  if (f)
    cout << "yes" << endl;
  else
    cout << "no" << endl;
  return 0;
}
