#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
bool getcell(vector<vector<bool>>& b, int i, int j) {
  if (i >= b.size() || j >= b[0].size() || i < 0 || j < 0) return false;
  return b[i][j];
}
bool isPlus(vector<vector<bool>>& b, int i, int j) {
  return getcell(b, i + 1, j) && getcell(b, i - 1, j) && getcell(b, i, j + 1) &&
         getcell(b, i, j - 1);
}
int genPlus(vector<vector<bool>>& b, int i, int j) {
  int ret = 0;
  int x, y;
  x = i;
  y = j;
  while (getcell(b, x + 1, y)) {
    ++x;
    ++ret;
  }
  x = i;
  y = j;
  while (getcell(b, x - 1, y)) {
    --x;
    ++ret;
  }
  x = i;
  y = j;
  while (getcell(b, x, y + 1)) {
    ++y;
    ++ret;
  }
  x = i;
  y = j;
  while (getcell(b, x, y - 1)) {
    --y;
    ++ret;
  }
  return ret;
}
int main(int argc, char const* argv[]) {
  cin.sync_with_stdio(0);
  cin.tie(0);
  int h, w;
  cin >> h >> w;
  int cnt = 0;
  vector<vector<bool>> there(h, vector<bool>(w));
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      char c;
      cin >> c;
      there[i][j] = (c == '*');
      cnt += there[i][j];
    }
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (there[i][j] && isPlus(there, i, j)) {
        int g = genPlus(there, i, j);
        if (g + 1 == cnt) {
          cout << "YES";
          return 0;
        }
        cout << "NO";
        return 0;
      }
    }
  }
  cout << "NO";
  return 0;
}
