#include<bits/stdc++.h>
using namespace std;
long long n,m,a[101],f[5001],p[101],q[101],x,y,gcd,t;
int main(){
    cin>>x>>y;
	cin>>n>>m;
    gcd=__gcd(x,y);
    y/=gcd;
    x/=gcd;
    for (int i=1;i<=m;i++){
        cin>>a[i];
        a[i]*=y;
    }
    for (int i=1;i<=n;i++) cin>>p[i]>>q[i];
    cin>>t;
    for (int i=1;i<=n;i++) for (int j=t;j>=a[i];j--) f[j]=max(f[j],f[j-a[p[i]]]+q[i]);
    cout<<f[t];
}