#include <bits/stdc++.h>
using namespace std;
long long read() {
  int f = 1;
  long long res = 0;
  char ch;
  do {
    ch = getchar();
    if (ch == '-') f = -f;
  } while (ch < '0' || ch > '9');
  do {
    res = res * 10 + ch - '0';
    ch = getchar();
  } while (ch >= '0' && ch <= '9');
  return f == 1 ? res : -res;
}
void fast_io() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
const int N = 510;
const int M = 3010;
const int mod = 1e9 + 7;
const long long INF = 1e18;
int n, m;
int A[N], B[N];
char str[N];
int head[N], to[N * 2], nxt[N * 2], tot;
void addEdge(int u, int v) {
  tot++;
  nxt[tot] = head[u];
  to[tot] = v;
  head[u] = tot;
}
template <class T>
T mmax(T a, T b) {
  return a < b ? b : a;
}
template <class T>
T mmin(T a, T b) {
  return a < b ? a : b;
}
int countOne(long long set) {
  int res = 0;
  while (set) {
    res++;
    set &= set - 1;
  }
  return res;
}
bool contain(long long set, int i) { return (set & (1LL << i)) > 0; }
long long myPow(long long a, int p) {
  if (p == 0) return 1;
  long long res = myPow(a, p / 2);
  res *= res;
  res %= mod;
  if (p % 2 == 1) {
    res *= a;
    res %= mod;
  }
  return res;
}
void addMode(long long &a, long long b) { a = (a + b) % mod; }
long long mul(long long a, long long b) { return a * b % mod; }
template <class T>
void mySwap(T &a, T &b) {
  T tmp = a;
  a = b;
  b = tmp;
}
char table[N][N];
int main() {
  fast_io();
  cin >> n >> m;
  for (int i = 0; i < n; i++) cin >> table[i];
  int cnt = 0;
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      if (table[i][j] == '*') cnt++;
  int dx[] = {-1, 0, 1, 0};
  int dy[] = {0, 1, 0, -1};
  for (int i = 0; i < n; i++)
    for (int j = 0; j < m; j++)
      if (table[i][j] == '*') {
        int cnt1 = 1;
        for (int k = 0; k < 4; k++) {
          int tmp = 0;
          int ni = i + dx[k];
          int nj = j + dy[k];
          while (ni >= 0 && ni < n && nj >= 0 && nj < m &&
                 table[ni][nj] == '*') {
            tmp++;
            ni = ni + dx[k];
            nj = nj + dy[k];
          }
          if (tmp == 0) {
            cnt1 = 0;
            break;
          } else {
            cnt1 += tmp;
          }
        }
        if (cnt1 == cnt) {
          cout << "YES" << endl;
          return 0;
        }
      }
  cout << "NO" << endl;
  return 0;
}
