N,M = map(int,input().split())
if N==1:
    ans = 0
elif N%2==0:
    ans = N*M
else:
    m = bin(M)[2:]
    K = len(m)
    k = -1
    cnt = 0
    for i in range(K):
        if m[i]=="1":
            cnt += 1
            if cnt==2:
                k = K-1-i
                break
    x = 1<<(K-1)
    for i in range(k):
        x += 1<<i
    y = M^x   
    ans = (N-2)*M
    ans += x+y
print(ans)