from itertools import combinations, product
N,M = list(map(int,input().split()))

def naive(N,M):
    ret = 0
    for i in product(range(M+1),repeat=N):
        tmp = 0
        for j in i:
            tmp ^= j
        if(tmp != 0):continue
        ret = max(ret, sum(i))
    return ret

def solve(N,M):
    if(N == 1):
        return 0
    elif(N%2 == 0):
        return M*N
    else:
        # のこりの3つで最大化
        A = [0,0,0]
        for i in range(30,-1,-1):
            if(A[1] + (1<<i) > M):continue
            A[0] += 1<<i
            A[1] += 1<<i
            A.sort()
        return M*(N-3) + sum(A)

if(N%2 == 0 or N == 1):print(solve(N,M))