from math import *
mmm = 0.0000001
D,H1,H2,H3 = [input() for i in "0000"]

def x1():
    h1,h2,h3 = H1,H2,H3
    ans = 0
    if (h1 <= h2):
        q = ceil(float(h2-h1)/D + mmm)
        ans += q
        h2 = max(h2-q*D,0)
    if (h3 <= h2):
        q = ceil(float(h2-h3)/D + mmm)
        ans += q
        h2 = max(h2-q*D,0)
    if (not h1 or not h3):
        return -1
    if (h1 == h3):
        return -1

    return ans

def x2():
    h1,h2,h3 = H1,H2,H3
    ans = 0
    if (h1 >= h2):
        q = ceil(float(h1-h2)/D + mmm)
        ans += q
        h1 = max(h1-q*D,0)
    if (h3 >= h2):
        q = ceil(float(h3-h2)/D + mmm)
        ans += q
        h3 = max(h3-q*D,0)
    if (not h2):
        return -1
    if (h1 == h3):
        return -1
    return ans
if (not D):
    if (H2 < H3 and H2 < H1 and H1 != H3):
        print 0
    elif (H2 > H3 and H2 > H1 and H1 != H3):
        print 0
    else:
        print -1
else:
    y1 = x1()
    y2 = x2()
    print int(y2) if (y1 == -1) else  int(y1)  if (y2 == -1) else int(min(y1,y2))