import sys
sys.setrecursionlimit(10**6)
A,B=map(int,input().split())
ans=0

def cal(a,b):
    global ans
    if a % 2 == 1 and b % 2 == 1:
        return 0
    if a < 0 or b < 0:
        return 0
    if a == 0 or b == 0:
        return 1

    else:
        if a%2==0:
            ans=max(cal(a//2,b-1),ans)
        if b%2==0:
            ans=max(cal(a-1,b//2),ans)

    return ans

    
print(cal(A,B))