A, B, S = map(int, input().split())
if abs(A - S) <= abs(B - S) or S == 1:
    print(abs(A - S) + S)
elif A < B:
    if A == 0:
        print(abs(B - S) + abs(A - S) + A + 1)
    else:
        print(abs(B - S) + abs(A - S) + A)
else:
    print(abs(B - S) + (A - S) + A)