#include <bits/stdc++.h>
using namespace std;
const int N = 1e3 + 5;
char a[N][N];
void fileIO() {}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  fileIO();
  int h, w;
  int tot = 0;
  cin >> h >> w;
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) {
      cin >> a[i][j];
      if (a[i][j] == '*') tot++;
    }
  int now = 0;
  int curi, curj;
  for (int i = 1; i < h - 1; i++) {
    for (int j = 1; j < w - 1; j++) {
      now = 0;
      if (a[i][j] == '*' and a[i + 1][j] == '*' and a[i - 1][j] == '*' and
          a[i][j + 1] == '*' and a[i][j - 1] == '*') {
        curi = i, curj = j;
        while (a[curi + 1][j] == '*') {
          now++;
          curi++;
        }
        curi = i, curj = j;
        while (a[curi - 1][j] == '*') {
          now++;
          curi--;
        }
        curi = i, curj = j;
        while (a[i][curj + 1] == '*') {
          now++;
          curj++;
        }
        curi = i, curj = j;
        while (a[i][curj - 1] == '*') {
          now++;
          curj--;
        }
        if (now + 1 == tot) {
          cout << "YES";
          exit(0);
        }
      }
    }
  }
  cout << "NO";
  return 0;
}
