A,B,S = map(int,input().split())

if abs(S-A) <= abs(S-B):
    print(abs(S-A)+S)
else:
    ans = abs(S-B)
    if A == 0:
        print(ans + S + 1)
    elif A < S:
        print(ans + S)
    else:
        print(ans + S + abs(S-A))