n, k = map(int, input().split())
if n%2 == 0:
    print(min(n//2, (k//2+1)*2))
elif n%2 != 0 and k%2 == 0:
    print(min(n, 2*(k//2)+1))
else:
    print(min(n, 2*((k+1)//2)))