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


double n, num, money, s, Min=10000000;

int main() {
	cin >> n;

	for (int i = 1; i < 4; i++)
	{
        cin >> num >>money;
		
		s = ceil(n / num) * money;
		if (s < Min) Min = s;
	}
	cout<<Min;

	

	return 0;
}