def dist(X,Y):
    return abs(X-Y)

A,B,S=map(int,input().split())
X=0
while S>0:
    if S==1:
        X+=dist(A,1)+dist(1,0)
        A=S=0
    else:
        if dist(A,S)<=dist(B,S):
            X+=dist(A,S)+dist(S,1)
            A=S=1
        else:
            X+=dist(B,S)+dist(S,1)
            B=S=1

print(X)