#include <bits/stdc++.h>
using namespace std;
long long int power(long long int x, long long int y);
long long int gcd(long long int a, long long int b);
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int h, w;
  cin >> h >> w;
  string s[h];
  for (long long int i = 0; i < h; i++) cin >> s[i];
  long long int f = 0, ci, cj;
  for (long long int i = 1; i < h - 1; i++) {
    for (long long int j = 1; j < w - 1; j++) {
      if (s[i][j] == '*') {
        long long int c = 0;
        if (s[i + 1][j] == '*') c++;
        if (s[i - 1][j] == '*') c++;
        if (s[i][j - 1] == '*') c++;
        if (s[i][j + 1] == '*') c++;
        if (c == 4) {
          f++;
          ci = i;
          cj = j;
        }
      }
    }
  }
  if (f != 1) {
    cout << "NO\n";
    return 0;
  } else {
    long long int flag = 0;
    for (long long int i = 0; i < h; i++) {
      for (long long int j = 0; j < w; j++) {
        if (s[i][j] == '*') {
          if (i != ci && j != cj) {
            flag = 1;
            break;
          }
        }
      }
    }
    if (flag) {
      cout << "NO\n";
      return 0;
    }
    long long int g = 0;
    for (long long int i = 0; i < h; i++) {
      if (g == 0) {
        if (s[i][cj] == '*') g = 1;
      } else if (g == 1) {
        if (s[i][cj] == '.') g = 2;
      } else {
        if (s[i][cj] == '*') {
          flag = 1;
          break;
        }
      }
    }
    if (flag) {
      cout << "NO\n";
      return 0;
    }
    g = 0;
    for (long long int i = 0; i < w; i++) {
      if (g == 0) {
        if (s[ci][i] == '*') g = 1;
      } else if (g == 1) {
        if (s[ci][i] == '.') g = 2;
      } else {
        if (s[ci][i] == '*') {
          flag = 1;
          break;
        }
      }
    }
    if (flag) {
      cout << "NO\n";
      return 0;
    }
    cout << "YES\n";
  }
}
long long int power(long long int x, long long int y) {
  long long int res = 1;
  x %= 1000000007;
  while (y > 0) {
    if (y & 1) res = (res * x) % 1000000007;
    y = y >> 1;
    x = (x * x) % 1000000007;
  }
  return res % 1000000007;
}
long long int gcd(long long int a, long long int b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
