def ceildiv(a: int, b: int) -> int:
    return (a + b - 1) // b


INF = 1 << 60
D = int(input())
H1 = int(input())
H2 = int(input())
H3 = int(input())

if D == 0:
    if H1 > H2 < H3 or H1 < H2 > H3:
        print(0)
    else:
        print(-1)
    exit()


# a > b > c にするのに必要な操作回数
def f(a, b, c):
    res = 0
    if a <= b:
        x = ceildiv(b-a, D)
        res += x
        b = max(0, b - x * D)
        if a == b:
            res += 1
            b -= D

    if b <= c:
        x = ceildiv(c-b, D)
        res += x
        c = max(0, c - x * D)
        if b == c:
            res += 1
            c -= D

    if a > b > c >= 0:
        return res
    return INF


ans = INF
# 真ん中が一番低い、または一番高い
for a, b, c in [(H2, H1, H3), (H2, H3, H1), (H1, H3, H2), (H3, H1, H2)]:
    res = f(a, b, c)
    ans = min(ans, res)

if ans == INF:
    print(-1)
else:
    print(ans)