#include<bits/stdc++.h>
using namespace std;
struct stu{
    int num;
    int m;
}s[5];
int main(){
    int n,minn=100000;
    cin>>n;
    for(int i=1;i<=3;i++){
        cin>>s[i].num>>s[i].m;
        for(int j=1;j<=n;j++){
            if(s[i].num*j>=n){
                minn=min(minn,s[i].m*j);
                break;
            }
        }
    }
    cout<<minn;
    return 0;
}