#include <bits/stdc++.h>
using namespace std;
void debug_out() { cerr << endl; }
void clock_out() {
  cerr << "\nTime Elapsed : " << 1.0 * clock() / CLOCKS_PER_SEC << " s\n";
}
void fileio() {
  freopen("/home/dwai/Desktop/cp/input.txt", "r", stdin);
  freopen("/home/dwai/Desktop/cp/output.txt", "w", stdout);
  freopen("/home/dwai/Desktop/cp/debug.txt", "w", stderr);
}
void ofileio() {
  freopen("input.txt", "r", stdin);
  freopen("output.txt", "w", stdout);
}
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << H;
  debug_out(T...);
}
int IT_MAX = 1 << 20;
const long long MOD = 1000000007;
const int INF = 0x3f3f3f3f;
const long long LL_INF = 0x3f3f3f3f3f3f3f3f;
const double PI = acos(-1);
const double ERR = 1e-10;
void solve() {
  long long n, m;
  cin >> n >> m;
  long long arr[n][m];
  long long i, j;
  long long cnt = 0;
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      char temp;
      cin >> temp;
      if (temp == '*') {
        arr[i][j] = 1;
        cnt++;
      } else
        arr[i][j] = 0;
    }
  }
  set<long long> r, c;
  for (i = 0; i < n; i++) {
    for (j = 1; j <= m - 1; j++) {
      if (arr[i][j] == 1 && arr[i][j - 1] == 1) {
        r.insert(i);
      }
    }
  }
  for (j = 0; j < m; j++) {
    for (i = 1; i <= n - 1; i++) {
      if (arr[i][j] == 1 && arr[i - 1][j] == 1) {
        c.insert(j);
      }
    }
  }
  if (r.size() != 1 || c.size() != 1) {
    cout << "NO";
    return;
  }
  long long x = *r.begin();
  long long y = *c.begin();
  long long curcnt = 0;
  for (i = x - 1; i >= 0; i--) {
    if (arr[i][y])
      curcnt++;
    else
      break;
  }
  for (i = y - 1; i >= 0; i--) {
    if (arr[x][i])
      curcnt++;
    else
      break;
  }
  for (i = x + 1; i <= n - 1; i++) {
    if (arr[i][y])
      curcnt++;
    else
      break;
  }
  for (i = y + 1; i <= m - 1; i++) {
    if (arr[x][i])
      curcnt++;
    else
      break;
  }
  curcnt++;
  if (arr[x][y] == 1 && cnt == curcnt) {
    if (x == 0 || y == 0 || x == n - 1 || y == m - 1) {
      cout << "NO";
      return;
    }
    if (arr[x - 1][y] == 1 && arr[x + 1][y] == 1 && arr[x][y - 1] == 1 &&
        arr[x][y + 1] == 1) {
      cout << "YES";
      return;
    }
  }
  cout << "NO";
}
int main() {
  42;
  ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  srand(time(NULL));
  solve();
  return 0;
}
