l=[*map(int,input().split())] print(min([abs(l[2]+l[3]-l[0]-l[1]),abs(l[1]+l[3]-l[0]-l[2]),abs(l[0]+l[3]-l[2]-l[1]),abs(l[0]+l[1]+l[2]-l[3]),abs(l[0]+l[1]+l[3]-l[2]),abs(l[1]+l[2]-l[3]-l[0]),abs(l[0]+l[3]-l[2]-l[1])]))