n=int(input())
[a,b]=[for i in input().split(" ")]
[c,d]=[for i in input().split(" ")]
[e,f]=[for i in input().split(" ")]
a1=b/a
a2=d/c
a3=f/e
tot=0
ls=[a1,a2,a3]
for i in range(1,4):
    maxn=min(ls)
    if maxn=a1:
        tot+=a*b*(n//a)
        n-=n//a
    if maxn=a2:
        tot+=c*d*(n//c)
        n-=n//c
    if maxn=a3:
        tot+=e*f*(n//e)
        n-=n//e
    ls.remove[maxn]
    maxn=min(ls)
print(tot)