d=int(raw_input())
H1=int(raw_input())
H2=int(raw_input())
H3=int(raw_input())
def kadomatsu(h1,h2,h3):
    if h1<h2 and h2>h3 and h1!=h3:
        return True
    if h1>h2 and h2<h3 and h1!=h3:
        return True
    return False

if kadomatsu(H1,H2,H3):
    print 0
    exit()
if d==0:
    print -1
    exit()
if H3<H1:
   H3,H1=H1,H3 

ans=3000000000
# case H1<H2>H3
t1,t2=max(0,(H1-H2+d)/d),max(0,(H3-H2+d)/d)
h1,h3=max(0,H1-t1*d),max(0,H3-t2*d)
if kadomatsu(h1,H2,h3):
    ans=min(ans,t1+t2)
elif h3>0 and max(h3-d,0)!=h1:
    ans=min(ans,t1+t2+1)

# case H1>H2<H3
if H1==H3:
    H1=max(0,H1-d)
t1=(H2-H1+d)/d
h2=max(0,t1*d)
if kadomatsu(H1,h2,H3):
    ans=min(ans,t1)
if ans==3000000000:
    ans=-1
print ans