#include <bits/stdc++.h>
using namespace std;

int main()
{
	int n, a1, a2, b1, b2, c1, c2;
	int p1, p2, p3;

	cin >> n >> a1 >> a2 >> b1 >> b2 >> c1 >> c2;

	p1 = ( n % a1 > 0 ? (n / a1 + 1) : (n / a1) ) * a2;
	p2 = ( n % b1 > 0 ? (n / b1 + 1) : (n / b1) ) * b2;
	p3 = ( n % c1 > 0 ? (n / c1 + 1) : (n / c1) ) * c2;

	cout << min(min(p1, p2), p3) << endl;
	return 0;
}