#include <cstdio>
#include <math.h>
#include <iostream>
using namespace std;
int main(){
    long int al = 1000000,a,b,c,co;
    cin >> c;
    for (int i = 1;i < 4;i++){
    	cin >> a >>b;
    	if (a!=0){
    	co = ceil((float)c/a);
    	co *= b;}
//    	cout << c/a << endl;
    	if ((co<al)){
    		al = co;
		}
	}
	cout << al;
}