#include<iostream>
using namespace std;
int main() {
	long long a;cin >> a;long long m, n;long long min = 9999999999, sum = 0;
	for (int i = 0;i < 3;i++) {
		cin >> m >> n;
		if (a / m == 0) { sum = a / m * n; }
		else { sum = a / m * n + n; }
		if (sum < min) { min = sum; }
		






	}


	cout << min << endl;


	return 0;
}