20
.*..*...*....*.....*
 97
****.***.***.*..**.**.*.*.***.*............*..*......*.***.**.*.***.*.***.*..*.**.*.***.**.*****.
 5
*.***
 4
****
 11
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 72
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 89
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 6
***.**
 54
...***.*...****.*..****....*..**..**..***.*..**...**..
 100
****************************************************************************************************
 53
*.*.****.*.*......**....**.***.*.*.**.*.*.***...*..*.
 87
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 90
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 55
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 21
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 41
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 31
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 64
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 10
*****....*
 99
**...*.*.*..*....**.***..*...***..***.**.*.....*.*....*...*.**.**.****..**..*.*..*.***....**...**.*
 69
.***...*.***.**...*....*.***.*..*....**.*...**....*.*..**....**..*.**
 99
.*.......................*.......................*.......................*.......................*.
 98
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 57
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 64
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 17
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 100
*...............................................................................................****
 11
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 1
.
 100
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 56
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 99
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 10
.*.*.*.*.*
 51
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 17
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 97
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 42
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 5
*****
 42
..*...*.*..**..*.*.*..**...**.***.*.******
 71
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 5
.****
 99
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 42
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 10
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 1
*
 5
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 16
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 100
*.......................*.......................*.......................*.......................*...
 7
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 58
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 67
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 99
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 6
......
 11
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 15
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 75
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 45
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 13
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 100
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 99
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 99
***************************************************************************************************
 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 main() {
  int n, m, t = 0, cnt;
  string s;
  cin >> n;
  cin >> s;
  if (s.size() < 5)
    cout << "no\n";
  else {
    for (int i = 0; i < n - 4; i++) {
      if (s.at(i) == '*' && s.at(i + 1) == '*' && s.at(i + 2) == '*' &&
          s.at(i + 3) == '*' && s.at(i + 4) == '*') {
        cout << "yes\n";
        t = 1;
        break;
      } else {
        if (s.at(i) != '.') {
          int k;
          m = 2;
          for (int j = i;;) {
            cnt = 0;
            for (k = j + m; k < n; k += m) {
              if (s.at(k) == '.') {
                m++;
                break;
              } else {
                cnt++;
                if (cnt == 4) {
                  cout << "yes\n";
                  t = 1;
                  break;
                }
              }
            }
            if (cnt == 4)
              break;
            else if (k >= n)
              break;
          }
        }
      }
      if (cnt == 4) break;
    }
    if (t == 0) cout << "no\n";
  }
  return 0;
}
