WA 0分，看看咋了？

#include <bits/stdc++.h>
#include <iostream>
#include <stdio.h>

using namespace std;

char a [ 500 + 10 ] [ 500 + 10 ];

int main ()
{
	ios::sync_with_stdio ( 0 );
	cin.tie ( 0 ), cout.tie ( 0 );
	int x, y;
	cin >> x >> y;
	for ( int i = 0; i < x; i ++ )
	{
		for ( int j = 0; j < y; j ++ )
		{
			cin >> a [ i ] [ j ];
		}
	}
	int cnt = 0;
	for ( int i = 0; i < x; i ++ )
	{
		for ( int j = 0; j < y; j ++ )
		{
			if ( a [ i ] [ j ] == '0' )
			{
				if ( a [ i + 1 ] [ j ] == '*' && a [ i - 1 ] [ j ] == '*' && a [ i ] [ j - 1 ] == '*' && a [ i ] [ j + 1 ] == '*' )
				{
					cnt ++;
				}
			}
		}
	}
	cout << cnt << endl;
	return 0;
}