#include<bits/stdc++.h>
using namespace std;
int main(){
	long long n,k,b,sum=0;
	cin>>n>>k>>b;
	while(n>0){
		long long x,y;
		cin>>x>>y;
		x=abs(x);
		y=abs(y);
		if(y==k*x+b){
			sum++;
		}
		n--;
	}
	printf("%lld\n",sum);
	return 0;
}

我哪错了？