N,M = map(int,input().split())
if N==1:
    ans = 0
elif N%2==0:
    ans = N*M
else:
    small = 0
    ans = 0
    for k in range(30,-1,-1):
        if M>>k & 1:
            ans += (N-1)*(1<<k)
            small += 1
            small = min(N,small)
        else:
            ans += (small-small%2)*(1<<k)
print(ans)