https://www.luogu.org/problem/P1909

"""
P1909 [NOIP2016 普及组] 买铅笔
https://www.luogu.org/problem/P1909
"""
min=0x7fffffff

n=int(input())

for i in range(1,4):

            num,price=map(int,input().split())

            if n%num==0:
                        bao=n//num
            else:
                        bao=n//num+1

            if bao*price<min:
                        min=bao*price

print(min)