#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  string s[h];
  for (int i = 0; i < h; i++) {
    cin >> s[i];
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (i == 0 || j == 0 || i == h - 1 || j == w - 1) continue;
      if (s[i][j] == '*' && s[i - 1][j] == '*' && s[i + 1][j] == '*' &&
          s[i][j - 1] == '*' && s[i][j + 1] == '*') {
        for (int p = j; p < w; p++) {
          if (s[i][p] != '*') break;
          s[i][p] = '1';
        }
        for (int p = j - 1; p >= 0; p--) {
          if (s[i][p] != '*') break;
          s[i][p] = '1';
        }
        for (int p = i + 1; p < h; p++) {
          if (s[p][j] != '*') break;
          s[p][j] = '1';
        }
        for (int p = i - 1; p >= 0; p--) {
          if (s[p][j] != '*') break;
          s[p][j] = '1';
        }
        for (int p = 0; p < h; p++) {
          for (int q = 0; q < w; q++) {
            if (s[p][q] == '*') {
              cout << "NO";
              return 0;
            }
          }
        }
        cout << "YES";
        return 0;
      }
    }
  }
  cout << "NO";
  return 0;
}
