#include<bits/stdc++.h>
using namespace std;
int main(){
	int a=0,b=0,c=0,d=0,e=0,f=0;
    scanf("%d",&a);
	scanf("%d%d",&b,&c);
    d=(a/b)*c;
    if(a%b!=0)d++;
    scanf("%d%d",&b,&c);
    e=(a/b)*c;
    if(a%b!=0)e++;
    scanf("%d%d",&b,&c);
    f=(a/b)*c;
    if(a%b!=0)f++;
    a=min({d,e,f});
    printf("%d",a);
return 0;
}