#include <bits/stdc++.h>
using namespace std;
const int inf = 1 << 30;
const long long maxn = 510;
int h, w;
char c[maxn][maxn];
int main() {
  int cnt = 0;
  cin >> h >> w;
  for (int i = 1; i <= h; ++i)
    for (int j = 1; j <= w; ++j) {
      cin >> c[i][j];
      if (c[i][j] == '*') ++cnt;
    }
  int cur = 0;
  ;
  for (int i = 1; i <= h; ++i)
    for (int j = 1; j <= w; ++j) {
      if (c[i][j] == '*' && c[i + 1][j] == '*' && c[i - 1][j] == '*' &&
          c[i][j + 1] == '*' && c[i][j - 1] == '*') {
        cur = cnt - 1;
        for (int k = 1; i + k <= h; ++k) {
          if (c[i + k][j] == '.') break;
          --cur;
        }
        for (int k = 1; j + k <= w; ++k) {
          if (c[i][j + k] == '.') break;
          --cur;
        }
        for (int k = 1; i - k > 0; ++k) {
          if (c[i - k][j] == '.') break;
          --cur;
        }
        for (int k = 1; j - k > 0; ++k) {
          if (c[i][j - k] == '.') break;
          --cur;
        }
        if (cur == 0) {
          cout << "YES\n";
          return 0;
        }
      }
    }
  cout << "NO\n";
  return 0;
}
