#include<bits/stdc++.h>
using namespace std;
int p[105],q[105],t[105],F[105];
int level_WKY,level_Wang,m,n,_time;
int main(){
	cin>>level_WKY>>level_Wang;
	cin>>m>>n;
	int mul=level_Wang/level_WKY;
	for(int i=1;i<=n;i++){
		cin>>p[i];
	}
	for(int i=1;i<=m;i++){
		int x;
		cin>>x;
		t[i]=p[x]*mul;
		cin>>q[i];
	}
	cin>>_time;
	for (int i = 1; i <= m; i++) {
		for (int j = _time; j >= t[i]; j--) {
			F[j] = max(F[j], F[j -t[i]]+q[i]);
		}
	}
	cout << F[_time];

	return 0;
}

五颜六色 AC2个 WA2个 RE1个