
int main()
{
	char a[102][102] , b[102][102];
	int n , i ,j;
	cin >> n;
	for (i = 0; i<= 101; i++)
		for (j = 0; j <= 101; j++)
		{
			a[i][j] = '#';
			b[i][j] = '#';
		}
	for (i = 1; i<=n ; i++)
		for (j = 1; j <= n; j++)
			cin >> a[i][j];
	int day , d;
	
	cin >> day;
	for (d = 2; d <= day; d++)
		if (d % 2 == 0)
			for (i = 1; i <= n ; i++)
				for (j = 1; j <= n; j++)
					if (a[i][j] != '#')
						if (a[i-1][j] == '@' || a[i+1][j] == '@' || a[i][j - 1] == '@'||a[i][j + 1] == '@'||a[i][j] == '@')
							b[i][j] = '@';
						else b[i][j] = '.';
					else b[i][j] = '#';
		else
			for (i = 1; i <= n ; i++)
				for (j = 1; j <= n; j++)
					if (b[i][j] != '#')
						if (b[i-1][j] == '@' || b[i+1][j] == '@' || b[i][j - 1] == '@'||b[i][j + 1] == '@'||b[i][j] == '@')
							a[i][j] = '@';
						else a[i][j] = '.';
					else a[i][j] = '#';
	int sum = 0;
	if (day % 2 == 0)
		for (i = 1; i <= n ; i++)		
			for (j = 1; j <= n; j++)
			{
				
				if (b[i][j] == '@')	
				sum ++;
				
			}
	else
		for (i = 1; i <= n ; i++)		
			for (j = 1; j <= n; j++)
			{
				
				if (a[i][j] == '@')	
				sum ++;
				
			}
	cout << sum << endl;
					





			




	return 0;





}