N = int(input())
A1, B1 = map(int,input().split())
A2, B2 = map(int,input().split())
A3, B3 = map(int,input().split())
if A2 * B1 < A1 * B2:
    A1, B1, A2, B2 = A2, B2, A1, B1
if A3 * B1 < A1 * B3:
    A1, B1, A3, B3 = A3, B3, A1, B1
print(
    max(
        t // A1 * B1 + p + q
        for p, s in zip(range(0, A1 * B2, B2), range(N, -1, -A2))
        for q, t in zip(range(0, A1 * B3, B3), range(s, -1, -A3))
    )
)