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

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