from collections import*
n,m=map(int,input().split())
d={0:n}
for i in range(30,-1,-1):
    x=1<<i
    p=defaultdict(int);c=-1
    for i in sorted(d):
        if i+x>m:p[i]+=d[i];continue
        if c>=0:p[c+x]+=1;p[i+x]+=1;d[i]-=1;c=-1
        if d[i]&1:c=i;d[i]-=1
        if d[i]:p[i+x]+=d[i]
    if c>=0:p[c]+=1
    d=p.copy()
print(sum(i*d[i]for i in d))