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)