#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w;
  cin >> h >> w;
  string value;
  vector<string> s;
  for (int i = 0; i < h; i++) {
    cin >> value;
    s.push_back(value);
  }
  int cnt = 0, l = 0, r = 0;
  bool flag = true;
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (s[i][j] == '*') {
        if (i >= 1 && i < h - 1 && j >= 1 && j < w - 1) {
          if (s[i - 1][j] == '*' && s[i + 1][j] == '*' && s[i][j - 1] == '*' &&
              s[i][j + 1] == '*') {
            cnt++;
            if (flag) {
              l = i;
              r = j;
            }
            flag = false;
          }
        }
      }
    }
  }
  if (cnt == 0 || cnt > 1)
    cout << "NO";
  else {
    int x = 0;
    int i = 0;
    int j = 0;
    while (i < w && s[l][i] == '.') {
      i++;
    }
    while (i < w && s[l][i] == '*') {
      if (i != r) s[l][i] = '.';
      i++;
    }
    while (j < h && s[j][r] == '.') j++;
    while (j < h && s[j][r] == '*') {
      s[j][r] = '.';
      j++;
    }
    for (int i = 0; i < h; i++) {
      for (int j = 0; j < w; j++) {
        if (s[i][j] == '*') {
          cout << "NO";
          return 0;
        }
      }
    }
    cout << "YES";
  }
}
