#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int w, h;
  cin >> w >> h;
  char arr[w + 2][h + 2];
  memset(arr, '.', sizeof(arr));
  for (int x = 1; x <= w; x++)
    for (int y = 1; y <= h; y++) cin >> arr[x][y];
  bool k = false;
  long long int r, c;
  for (int x = 1; x <= w; x++)
    for (int y = 1; y <= h; y++) {
      if (arr[x][y] == '*' && arr[x][y - 1] == '*' && arr[x - 1][y] == '*' &&
          arr[x + 1][y] == '*' && arr[x][y + 1] == '*') {
        if (!k)
          k = true;
        else
          k = false;
        r = x;
        c = y;
        break;
      }
    }
  if (k) {
    for (int x = 1; x <= w; x++)
      for (int y = 1; y <= h; y++) {
        if (arr[x][y] == '*' && (r != x && c != y)) {
          k = false;
        }
      }
    if (k) {
      for (int x = 1; x <= h; x++) {
        if (arr[r][x] == '*') {
          if (c > x) {
            if (arr[r][x + 1] != '*') k = false;
          } else {
            if (arr[r][x - 1] != '*') k = false;
          }
        }
      }
      for (int x = 1; x <= w; x++) {
        if (arr[x][c] == '*') {
          if (r > x) {
            if (arr[x + 1][c] != '*') k = false;
          } else {
            if (arr[x - 1][c] != '*') k = false;
          }
        }
      }
    }
  }
  if (k)
    cout << "YES";
  else
    cout << "NO";
}
