#include<bits/stdc++.h>
using namespace std;
long long a,b,c,d,e,f,k,ay,by,am,bm;
int main(){
    scanf("%lld%lld%lld%lld%lld%lld%lld",&a,&b,&c,&d,&e,&f,&k);
    ay=k/a*b; by=k/d*e;
    am=k/a*a*c; bm=k/e*e*f;
    if(am>bm&&ay<=k) printf("%lld",am);
    else printf("%lld",bm);
    return 0;
}