//****************************
//*???:5.cpp               *
//*??:??                  *
//*????:2013?11?11?     *
//*????:????           *
//****************************
int main()
{
	//????????a[][]
	char a[102][102];
	int n, i, j, ill, p, m;  //?????n???,????i,j,p,????ill,??m
	cin >> n;
	ill = 0;
	for ( i = 0; i <= n + 1; i ++ )  //???????????,?????????????????
		for ( j = 0; j <= n + 1; j ++ )
			a[i][j] = '#';
	for ( i = 1; i <= n; i ++ )  //?????????????
		for ( j = 1; j <= n; j ++ )
			cin >> a[i][j];
	cin >> m;
	for ( p = 1; p < m; p ++ )  //???????????
	{
		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] = '*';  //???????????,??????????????
			}
		for ( i = 1; i <= n; i ++ )  //????????????'*'?????????
			for ( j = 1; j <= n; j ++ )
			{
				if ( a[i][j] == '*' )
					a[i][j] = '@';
			}
	}
	for ( i = 1; i <= n; i ++ )  //????????????????
		for ( j = 1; j <= n; j ++ )
		{
			if ( a[i][j] == '@' )
				ill ++;
		}
	cout << ill;
	return 0;
}