#include <bits/stdc++.h>
using namespace std;
int main() {
  int h, l;
  char a[1010][1010];
  cin >> h >> l;
  int u = 0, po = 0;
  for (int i = 1; i <= h; i++) cin >> a[i] + 1;
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= l; j++) {
      if (a[i][j] == '*') po = 1;
      if (a[i][j] == '*' && a[i + 1][j] == '*' && a[i - 1][j] == '*' &&
          a[i][j + 1] == '*' && a[i][j - 1] == '*') {
        a[i][j] = '.', a[i + 1][j] = '.', a[i - 1][j] = '.', a[i][j + 1] = '.',
        a[i][j - 1] = '.';
        int x = i + 2, y = j;
        while (a[x][y] == '*') a[x++][y] = '.';
        x = i - 2, y = j;
        while (a[x][y] == '*') a[x--][y] = '.';
        x = i, y = j - 2;
        while (a[x][y] == '*') a[x][y--] = '.';
        x = i, y = j + 2;
        while (a[x][y] == '*') a[x][y++] = '.';
        u = 1;
      }
      if (u) break;
    }
    if (u) break;
  }
  for (int i = 1; i <= h; i++) {
    for (int j = 1; j <= l; j++) {
      if (a[i][j] == '*') {
        printf("NO\n");
        return 0;
      }
    }
  }
  if (po)
    printf("YES\n");
  else
    printf("NO\n");
  return 0;
}
