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

ok = 0
ng = 0
while (A > 0) and (B > 0):
    ng += 2
    A -= 1
    B -= 1
    if A+B < 2:
        break
    if A > B:
        A -= 2
    elif B > A:
        B -= 2
    else:
        A -= 1
        B -= 1
    ok += 2
ok += A
ok += B

print(abs(ok-ng))