# include <bits/stdc++.h>

# define re register

# define N 5050

using namespace std;

int n,a,b,c;

int ans;

struct node

{

int h;//高度

int v;//速度

int sum;

}e[N];

int cmp1(const node &a,const node &b) {return a.h>b.h;}//按高度排序

int cmp2(const node &a,const node &b) {return a.sum>b.sum;}//按总属性排序

node f[N];

int main()

{

ios::sync_with_stdio(false);

cin>>n>>a>>b>>c;

for(int i = 1; i <= n; i++)

{

cin>>e[i].h>>e[i].v;

e[i].sum = a*e[i].h + b*e[i].v;//总属性

f[i] = e[i];

}

sort(e+1,e+n+1,cmp1);

sort(f+1,f+n+1,cmp2);

int l,r,cnt;

for(int i = 1; i <= n; i++)

{

l = r = 0;

cnt = 0;

int maxn = e[i].v + c/b;

for(int j = 1; j <= n; j++)

{

while(r < n && f[r+1].sum <= a*e[j].h+b*e[i].v+c)

{

r++;

if(f[r].v >= e[i].v && f[r].v <= maxn) cnt++;

}

while(l < n && e[l+1].h < e[j].h)

{

l++;

if(e[l].v >= e[i].v && e[l].v <= maxn) cnt--;

}

}

ans = max(ans , cnt);

}

cout<<ans<<endl;

return 0;

}