#include<bits/stdc++.h>

using namespace std;

double n,minx;
double n1,n2,n3,p1,p2,p3;
int sum1,sum2,sum3;

int main() {
    
	cin >> n;
	cin >> n1 >> p1;
	cin >> n2 >> p2;
	cin >> n3 >> p3;
	sum1 = ceil(n/n1)*p1;
	sum2 = ceil(n/n2)*p2;
	sum3 = ceil(n/n3)*p3;
	//cout << sum1 << " " << sum2 << " " << sum3 << endl;
	minx = min(sum1,min(sum2,sum3));
	cout << minx;
	
    return 0;
}