#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    int n,p1,a1,p2,a2,p3,a3;
    cin>>n>>p1>>a1>>p2>>a2>>p3>>a3;
    int n1,n2,n3;
    do{
        if(p1*a1>=n){
            n1=p1*a1;
        }
        if(p2*a2>=n){
            n2=p2*a2;
        }
        if(p3*a3>=n){
            n3=p3*a3;
        }
        a1+=a1;
        a2+=a2;
        a3+=a3;
    }
    while(p1*a1<n||p2*a2<n||p3*a3<n);
    cout<<(a1>a2?(a1>a3?a1:a3):a2);
    return 0;
}