#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, w, ii, jj, ans = 0;
  cin >> h >> w;
  char a[505][505];
  for (int i = 0; i < h; i++)
    for (int j = 0; j < w; j++) cin >> a[i][j];
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (a[i][j] == '*') {
        if ((i - 1 >= 0 && a[i - 1][j] == '*') &&
            (j - 1 >= 0 && a[i][j - 1] == '*') &&
            (i + 1 <= h - 1 && a[i + 1][j] == '*') &&
            (j + 1 <= w - 1 && a[i][j + 1] == '*')) {
          ii = i;
          jj = j;
          ans = 1;
          while (ii >= 0 && a[ii][jj] == '*') {
            a[ii][jj] = '@';
            ii--;
          }
          ii = i;
          a[ii][jj] = '*';
          while (jj >= 0 && a[ii][jj] == '*') {
            a[ii][jj] = '@';
            jj--;
          }
          jj = j;
          a[ii][jj] = '*';
          while (ii < h && a[ii][jj] == '*') {
            a[ii][jj] = '@';
            ii++;
          }
          ii = i;
          a[ii][jj] = '*';
          while (jj < w && a[ii][jj] == '*') {
            a[ii][jj] = '@';
            jj++;
          }
          jj = j;
          break;
        }
      }
    }
    if (ans == 1) break;
  }
  if (ans == 0) {
    cout << "NO";
    return 0;
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (a[i][j] == '*') ans = 0;
    }
  }
  if (ans == 0) {
    cout << "NO";
  } else
    cout << "YES";
}
