#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m, flag = 0, x = 0, y = 0;
  cin >> n >> m;
  string a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  if (n < 3 || m < 3) {
    cout << "NO";
    return 0;
  }
  int l, w;
  for (l = 1; l < n - 1; l++) {
    for (w = 1; w < m - 1; w++) {
      if ((a[l][w] == '*') && (a[l + 1][w] == '*') && (a[l][w + 1] == '*') &&
          (a[l - 1][w] == '*') && (a[l][w - 1] == '*')) {
        x = l;
        y = w;
        flag = 1;
        goto finish;
      }
    }
  }
finish:
  if (flag == 1) {
    for (int i = y; i < m; i++) {
      if (a[x][i] == '*') {
        a[x][i] = '.';
      } else
        break;
    }
    for (int i = y - 1; i >= 0; i--) {
      if (a[x][i] == '*') {
        a[x][i] = '.';
      } else
        break;
    }
    for (int i = x + 1; i < n; i++) {
      if (a[i][y] == '*') {
        a[i][y] = '.';
      } else
        break;
    }
    for (int i = x - 1; i >= 0; i--) {
      if (a[i][y] == '*') {
        a[i][y] = '.';
      } else
        break;
    }
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        if (a[i][j] == '*') {
          cout << "NO";
          return 0;
        }
      }
    }
    cout << "YES";
  } else {
    cout << "NO";
  }
  return 0;
}
