#include<bits/stdc++.h>
using namespace std;
int main()
{
    int h=3,n,money,ans=1000000010;scanf("%d",&n);
    while(h--)
    {
        int a,b;cin>>a>>b;
        if(n<a)money=b;
        else money=ceil(n/a*1.0)*b;
        ans=min(ans,money);
    }
    cout<<ans;
}