#include <iostream>
#include <bits/stdc++.h>
using namespace std;
struct pencil{
	int num;
	int price;
}pp[10005];

int times(int x , int n){
	int a;
	for(int i = 1 ;;i++){
		if(i*x >= n){
			a = i;
			break;
		}
	}
	return (a);
}

int main()
{
	int n;
	cin >> n;
	int a,b,c;
	for(int i = 1 ;i <= 3 ;i++){
		cin >> pp[i].num >> pp[i].price;
    }
    a = times(pp[1].num , n) * pp[1].price;
	b = times(pp[2].num , n) * pp[2].price;
	c = times(pp[3].num , n) * pp[3].price;

	int m[4];
	m[1] = a;
	m[2] = b;
	m[3] = c;
	sort(m + 1 , m + 4);
	cout << m[1];
	return 0;
}