#include <bits/stdc++.h>
using namespace std;
const long long N = 1e5 + 5;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  vector<pair<long long, long long> > v;
  long long n, m;
  cin >> n >> m;
  char a[505][505];
  long long c = 0;
  for (long long i = 1; i <= n; i++) {
    for (long long j = 1; j <= m; j++) {
      cin >> a[i][j];
      if (a[i][j] == '*') {
        c++;
      }
    }
  }
  for (long long i = 1; i <= n; i++) {
    for (long long j = 1; j <= m; j++) {
      if (a[i][j] == '*' && a[i - 1][j] == '*' && a[i + 1][j] == '*' &&
          a[i][j - 1] == '*' && a[i][j + 1] == '*') {
        { v.push_back({i, j}); }
      }
    }
  }
  if (v.size() == 0) {
    cout << "NO"
         << "\n";
    return 0;
  }
  for (auto it : v) {
    long long x = it.first;
    long long y = it.second;
    long long ans = 0;
    long long i = x - 1;
    while (a[i][y] == '*') {
      ans++;
      i--;
    }
    i = x + 1;
    while (a[i][y] == '*') {
      ans++;
      i++;
    }
    i = y + 1;
    while (a[x][i] == '*') {
      ans++;
      i++;
    }
    i = y - 1;
    while (a[x][i] == '*') {
      ans++;
      i--;
    }
    if (ans + 1 == c) {
      cout << "YES"
           << "\n";
      return 0;
    }
  }
  cout << "NO"
       << "\n";
}
