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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
import java.util.*;
import java.io.*;
 
public class a {
  public static void main(String[] args) {
    InputReader in = new InputReader();
    in.init(System.in);

    Solver soal = new Solver();
    soal.solve(in);
  }
}

class Solver {
  private char[] s;
  private int N;
  private int[][] hs;
  
  public void solve(InputReader in) {
    N = in.nextInt();
    s = in.next().toCharArray();
    hs = new int[N][N];
    for (int i = 0; i < N; ++i) {
      for (int j = 0; j < N; ++j) {
        hs[i][j] = 0;
      }
    }
    for (int i = 1; i <= N; ++i) {
      for (int j = 0; j < N; ++j) {
        if (s[j] == '*')
          hs[i - 1][j % i]++;
      }
    }
    boolean is = false;
    for (int i = 0; i < N; ++i) {
      for (int j = 0; j < N; ++j) {
        if (hs[i][j] > 4) is = true;
      }
    }
    System.out.println(is ? "yes" : "no");
  }
}

class InputReader {
  private BufferedReader reader;
  private StringTokenizer tokenizer;

  public void init(InputStream input) {
    reader = new BufferedReader(
            new InputStreamReader(input), 
            32768);
    tokenizer = null;
  }

  public String next() {
    while (tokenizer == null || !tokenizer.hasMoreTokens()) {
      try {
        tokenizer = new StringTokenizer(reader.readLine());
      } catch (Exception e) {
        throw new RuntimeException(e);
      }
    }
    return tokenizer.nextToken();
  }

  public int nextInt() {
    return Integer.parseInt(next());
  }
  
  public long nextLong() {
    return Long.parseLong(next());
  }
}



