#include<bits/stdc++.h> typedef long long ll; using namespace std; const int N=10010; struct asd{ int number; int price; int price_sum; }; asd a[N]; int s[N]; int n; int sum; int m=1e7; int main(){

cin.sync_with_stdio(false);
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
cin>>n;
for(int i=1;i<=3;i++){
	cin>>a[i].number>>a[i].price;
	while(sum*a[i].number<n)sum++;
	a[i].price_sum=sum*a[i].price;
	if(m>a[i].price_sum){
		m=a[i].price_sum;
	}		
	sum=0;
}
cout<<m;


return 0;

}