#include <bits/stdc++.h>
using namespace std;
int main()
{
    long long n,k,b;
    cin >> n >> k >> b;
    int cnt = 0;
    for (int i = 1; i <= n; ++i) {
	int x, y;
	cin >> x >> y;
	long long m=1ll*k*x+b;
	if (y == m);
   		++cnt;
    }
    cout << cnt << endl;
    return 0;
}