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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;
int n, i, j, ok, v[500];
string s;
void verifica(int start, int pas) {
  int steps = 0;
  int oktura = 1;
  while (steps < 4) {
    if (v[start] == 0) oktura = 0;
    start = start + pas;
    steps++;
  }
  if (oktura) ok = 1;
}
int main() {
  cin >> n;
  cin >> s;
  for (i = 1; i <= n; i++) {
    if (s[i - 1] == '*')
      v[i] = 1;
    else
      v[i] = 0;
  }
  ok = 0;
  int nr = 0;
  int maxi = 0;
  for (i = 1; i <= n; i++) {
    if (v[i] == 0) nr++;
    if (nr > maxi) maxi = nr;
    if (v[i] == 1) nr = 0;
  }
  for (i = maxi + 1; i <= n / 2 and ok == 0; i++) {
    for (j = 1; j <= n; j++) {
      if (v[j] == 1) verifica(j, i);
    }
  }
  if (ok)
    cout << "yes";
  else
    cout << "no";
}
