#include<iostream>
#include<cstring>
#include<iomanip>
#include<cmath>
#include<algorithm>
#define ll long long
#define ull unsigned long long
using namespace std;
float n;
float number1,number2,number3;	//三个包装铅笔的数量
int price1,price2,price3;	//三个包装铅笔的价格 
int main()
{
	cin>>n;
	cin>>number1>>price1;
	cin>>number2>>price2;
	cin>>number3>>price3;
	if(number1==0||number2==0||number3==0)
	{
		cout<<0;
		return 0;
	}
	float a=ceil(n/number1)*price1;
	float b=ceil(n/number2)*price2;
	float c=ceil(n/number3)*price3;		//每种包装所需的最低价格
	cout<<min(min(a,b),c); 
	return 0;
}