d=int(input())
H=[int(input()) for i in range(3)]

if d==0:
    if H[1]>H[0] and H[1]>H[2] and H[0]!=H[2]:
        print(0)
        exit()
    if H[1]<H[0] and H[1]<H[2] and H[0]!=H[2]:
        print(0)
        exit()
    print(-1)
    exit()
A=1<<60

# H[1]>H[0],H[2]にする

k=max(0,(H[0]-H[1])//d+1)
l=max(0,(H[2]-H[1])//d+1)

X=[max(0,H[0]-d*k),H[1],max(0,H[2]-d*l)]

if X[1]>X[0] and X[1]>X[2]:
    if X[0]!=X[2]:
        A=k+l
    elif X[0]!=0 or X[2]!=0:
        A=k+l+1
    else:
        A=1<<60

# H[1]<H[0],H[2]にする

k=0
B=1<<60

if H[0]==H[2]:
    H[0]=max(0,H[0]-d)
    k+=1

k+=max(0,(H[1]-min(H[0],H[2]))//d+1)


X=[H[0],max(0,H[1]-d*k),H[2]]

if X[1]<X[0] and X[1]<X[2]:
    if X[0]!=X[2]:
        B=k
    else:
        B=1<<60

ANS=min(A,B)

if ANS==1<<60:
    print(-1)
else:
    print(ANS)