```cpp
#include<iostream>
#include<cstdio>
#include<set>
using namespace std;
int n,sx,sy;
int x[100005];
int y[100005];
set<long long>s;
void insert(int x,int y){
long double f=(double)(x-sx)/(y-sy);
long long res=f*1e8;
s.insert(res);
}
int main(){
scanf("%d",&n);
for(int i=1;i<=n;i++)scanf("%d%d",&x[i],&y[i]);
scanf("%d%d",&sx,&sy);
for(int i=1;i<=n;i++)insert(x[i],y[i]);
printf("%d\n",s.size());
return 0;
}
```