d = input()
H = []
for i in range(3):
    H.append(input())


def upward():
    if H[1] == 0:
        return None
    if H[0] < H[1] and H[1] > H[2] and H[0] != H[2]:
        return 0
    if d == 0:
        return None
    x = [0, 0, 0]
    y = list(H)
    z = 0
    for i in [0, 2]:
        if H[i] >= H[1]:
            x[i] = max((H[i] - H[1]) / d, -1) + 1
            y[i] = max(0, H[i] - d * x[i])
    if y[0] == y[2]:
        y[0] -= d
        z += 1
    if y[0] < 0:
        return None
    return sum(x) + z


def downward():
    z = 0
    if H[1] < H[0] and H[1] < H[2] and H[0] != H[2]:
        return 0
    if d == 0:
        return None
    if H[0] == H[2]:
        H[0] -= d
        z += 1
    if H[0] <= 0 or H[2] <= 0:
        return None
    y = min(H[0], H[2])
    return max((H[1] - y) / d, -1) + 1 + z

ans = [x for x in [upward(), downward()] if x is not None]
if len(ans) == 0:
    print(-1)
else:
    print(min(ans))