D, A, B, C = input(), input(), input(), input()

if A > C:
    A, C = C, A
    
if A == 0 or C == 0:
    print -1
elif A == B == C:
    print 3 if B > D else -1
elif A < B < C:
    m1 = (B-A)/D + ((B-A)%D==0)
    m2 = (C-B)/D + ((C-D)%D==0)
    if (C-A)%D == 0 and A+D == B:
        m2 += 1
    print min(m1, m2)
elif A == B < C:
    print 1
elif A < B == C:
    if C - D != A:
        print 1
    else:
        print 2
else:
    print 0