n = int(input())
n1,n2 = n,n
t,j,k = 0,0,0
l = []
m = []
for i in range(3):
    l.append(list(map(int,input().split())))
while n > 0:
   n -= l[0][0]
   t += l[0][1]
m.append(t)
while n1 > 0:
   n1 -= l[1][0]
   j += l[1][1]
m.append(j)
while n2 > 0:
   n2 -= l[2][0]
   k += l[2][1]
m.append(k)
m.sort()
print(m[0])