N,M=map(int,input().split())

if N%2==0:
    print(N*M)
    exit()

A=[0,0]

for i in range(33):
    if (1<<i) & M !=0:
        ind=i

A[0]=(1<<ind)
A[1]=M^(1<<ind)

for i in range(33,-1,-1):
    if (1<<i) & M!=0:
        continue
    if max(A[0],A[1])+(1<<i)<=M:
        A[0]+=(1<<i)
        A[1]+=(1<<i)

ANS=(N-2)*M+sum(A)

print(ANS)