#include <bits/stdc++.h>
using namespace std;
const int N = 5e3 + 5;
long long mod = 998244353;
int n, m;
char s[N][N];
long long x, y, z;
int main() {
  std::ios::sync_with_stdio(0);
  ;
  cin >> n >> m;
  for (int i = 1; i <= n; i++) {
    cin >> s[i] + 1;
  }
  int h = 0;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++)
      if (s[i][j] == '*') h++;
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m; j++) {
      if (s[i][j] == '*') {
        int g = 1;
        int flag1 = 0, flag2 = 0, flag3 = 0, flag4 = 0;
        for (int k = i - 1; k >= 1; k--) {
          if (s[k][j] == '*') {
            flag1++;
            g++;
          } else
            break;
        }
        for (int k = i + 1; k <= n; k++) {
          if (s[k][j] == '*') {
            g++;
            flag2++;
          } else
            break;
        }
        for (int k = j - 1; k >= 1; k--) {
          if (s[i][k] == '*') {
            g++;
            flag3++;
          } else
            break;
        }
        for (int k = j + 1; k <= m; k++) {
          if (s[i][k] == '*') {
            g++;
            flag4++;
          } else
            break;
        }
        if (g == h && g >= 5 && flag1 && flag2 && flag3 && flag4) {
          cout << "YES" << endl;
          return 0;
        }
      }
    }
  }
  cout << "NO" << endl;
}
