#include <iostream>
using namespace std;

int main() {
	int n, pencil;
	int money1, money2, money3;
	int bao1pencil, bao1money;
	int bao2pencil, bao2money;
	int bao3pencil, bao3money;
	
	cin >> n;
	cin >> bao1pencil >> bao1money;
	cin >> bao2pencil >> bao2money;
	cin >> bao3pencil >> bao3money;
	
	for(pencil = 0; pencil <= n; pencil += bao1pencil)
		money1 += bao1money;
	for(pencil = 0; pencil <= n; pencil += bao2pencil)
		money2 += bao2money;
	for(pencil = 0; pencil <= n; pencil += bao3pencil)
		money3 += bao3money;

	int money = min(min(money1, money2), money3);
		
	cout << money << endl;
	return 0;
}