#include<bits/stdc++.h>

using namespace std;

struct yangs
{
	double shul;
	double jiag;
};

int main()
{
	double sl, min = 0x3f3f3f3f;
	cin >> sl;
	yangs a;
	for(int i = 0; i < 3; i++)
	{
		cin >> a.shul >> a.jiag;
		double bs = ceil(sl/a.shul * 1.0);
		if(bs * a.jiag < min)min = bs * a.jiag;
	}
	
	cout << min;
	
	return 0;	
}