#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w, x, y, star = 0, sum, flag;
  char arr[505][505];
  cin >> h >> w;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= w; j++) {
      cin >> arr[i][j];
      if (arr[i][j] == '*') {
        star++;
        if (arr[i][j - 1] == '*' && arr[i - 1][j] == '*') {
          sum = 3;
          x = i;
          y = j;
        }
      }
    }
  }
  if (sum == 3) {
    if (arr[x][y + 1] == '*' && arr[x + 1][y] == '*') {
      sum = sum + 2;
    }
    if (sum == 5) {
      flag = 1;
      if (x + 2 <= h) {
        for (int i = x + 2; i <= h; i++) {
          if (arr[i][y] == '*')
            sum++;
          else
            break;
        }
      }
      if (x - 2 > 0) {
        for (int i = x - 2; i > 0; i--) {
          if (arr[i][y] == '*')
            sum++;
          else
            break;
        }
      }
      if (y + 2 <= w)
        for (int i = y + 2; i <= w; i++) {
          if (arr[x][i] == '*')
            sum++;
          else
            break;
        }
      if (y - 2 > 0) {
        for (int i = y - 2; i > 0; i--) {
          if (arr[x][i] == '*')
            sum++;
          else
            break;
        }
      }
    }
  }
  if (star == sum && sum >= 5)
    cout << "YES";
  else
    cout << "NO";
  return 0;
}
