from math import ceil
d = int(input())
H = [int(input()) for _ in range(3)]
if (H[0] < H[1] and H[1] > H[2]) or (H[0] > H[1] and H[1] < H[2]):
    print(0)
elif (H[1] == 0 and (H[0] == 0 or H[2] == 0)) or d == 0:
    print(-1)
else:
    ans = ceil(max(0, H[0] - H[1]) / d) + ceil(max(0, H[2] - H[1]) / d)
    if H[0] >= H[1] and (H[0] - H[1]) % d == 0:
        ans += 1
    if H[2] >= H[1] and (H[2] - H[1]) % d == 0:
        ans += 1
    if H[0] != 0 and H[2] != 0:
        cand = ceil((H[1] - min(H[0], H[2])) / d)
        if (H[1] - min(H[0], H[2])) % d == 0:
            cand += 1
        ans = min(ans, cand)
    print(ans)