#include <bits/stdc++.h>
using namespace std;
char pic[505][505];
int cntX[505] =
    {
        0,
},
    cntY[505] =
        {
            0,
},
    cnt = 0;
int main() {
  int h, w;
  scanf("%d %d", &h, &w);
  for (int i = 0; i < h; i++) {
    scanf("%s", pic[i]);
    for (int j = 0; j < w; j++) {
      if (pic[i][j] == '*') {
        cnt++;
      }
    }
  }
  for (int i = 0; i < h; i++) {
    for (int j = 0; j < w; j++) {
      if (pic[i][j] == '.') continue;
      int l = 0, r = 0, u = 0, d = 0;
      for (int k = i + 1; k < h; k++) {
        if (pic[k][j] == '*')
          d++;
        else
          break;
      }
      for (int k = i - 1; k >= 0; k--) {
        if (pic[k][j] == '*')
          u++;
        else
          break;
      }
      for (int k = j + 1; k < w; k++) {
        if (pic[i][k] == '*')
          r++;
        else
          break;
      }
      for (int k = j - 1; k >= 0; k--) {
        if (pic[i][k] == '*')
          l++;
        else
          break;
      }
      if (l != 0 && r != 0 && u != 0 && d != 0 && d + u + r + l + 1 == cnt) {
        printf("YES");
        return 0;
      }
    }
  }
  printf("NO");
  return 0;
}
