A,B,C = [int(i) for i in input().split()]
X = int(input())

def ont(S):
    a,b,c = S
    L = []
    if a > 0:
        if b < B:
            x = min(a,B-b)
            L.append((a-x,b+x,c))
        if c < C:
            x = min(a,C-c)
            L.append((a-x,b,c+x))
    if b > 0:
        if a < A:
            x = min(b,A-a)
            L.append((a+x,b-x,c))
        if c < C:
            x = min(b,C-c)
            L.append((a,b-x,c+x))
    if c > 0:
        if a < A:
            x = min(c,A-a)
            L.append((a+x,b,c-x))
        if b < B:
            x = min(c,B-b)
            L.append((a,b+x,c-x))
    return L

def BFS(S):
    sor = [S]
    lepes = {}
    lepes[S] = 0
    while sor != []:
        P = sor.pop(0)
        L = ont(P)
        for viz in L:
            if viz not in lepes:
                sor.append(viz)
                lepes[viz] = lepes[P] + 1
                if X in viz:
                    return lepes[viz]
    return -1

if A == X:
    print(0)
else:
    print(BFS((A,0,0)))