#include<bits/stdc++.h>
using namespace std;
int main(){
	double n;
	cin>>n;
	double minn=0x3f3f3f3f3f;
	for(int i=0;i<3;i++){
		double num,mon;
		cin>>num>>mon;
		minn=min(minn,ceil(n/num)*mon);
	} 
	cout<<minn;
	return 0;
}