<>;
for(<>){
	/ /;
	$x=$`/15;
	$y=$'/15;
	for$y($y..$y+2){
		for$x($x..$x+2){
			if((($_[$y][$x][0]//-20)-$`)**2+($_[$y][$x][1]-$')**2<400){
				goto a
			}
		}
	}
	$_[$y+1][$x+1]=[$`,$'];
	++$z;
	a:
}
print$z