($a,$b)=($p,$q)=<>=~/\d+/g;
($a,$b)=($b,$a%$b)while$b;
$a||=1e9;
$p/=$a;$q/=$a;
<>;
($x,$y)=//g,$x%$a||$y%$a||$p%2&&$q%2&&($x+$y)/$a%2||++$-for<>;
print$-;