#include<stdio.h>
int main(){
    int num, n1, m1, n2, m2, n3, m3;
    int a, b, c, p1, p2, p3, x;
    scanf("%d",&num);
    scanf("%d%d",&n1,&m1);
    scanf("%d%d",&n2,&m2);
    scanf("%d%d",&n3,&m3);
    a=num/n1;
    b=num/n2;
    c=num/n3;
    if(num%n1!=0){
        a++;
        p1=a*m1;
    }else
    p1=a*m1;
    if(num%n2!=0){
        b++;
        p2=b*m2;
    }else
    p2=b*m2;
    if(num%n3!=0){
        c++;
        p3=c*m3;
    }else
    p3=c*m3;
    x=(p1<p2)?p1:p2;
    x=(p1<p3)?p1:p3;
    x=(p3<p2)?p3:p2;
    printf("%d",x);
    return 0;
}