$n=<>+0;$a=<>.<>;$r=0;
for$j(0..13){
	$_=$a;s/\n//;pos=$j;s/\Gx{0,$n}/o x length$&/e;
	$x=0;$i=0;
	/o/?$r+=$-=++$x-$r:($x=0),$i++for/./g;
}
print$r