#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,a,aa,b,bb,c,cc;cin>>n>>a>>aa>>b>>bb>>c>>cc;
    cout<<min(ceil(n*1.0/a)*aa,min(ceil(n*1.0/b)*bb,ceil(n*1.0/c)*cc));
}