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

a = M
ans=a
ac=M
count=0
while ac>1:
    if ac % 2 == 0:
        ac //= 2
        count+=1
    else:
        ac = ac // 2 + 1
        count+=1

if count>=N:
    print(2**N-1)
    exit()

for i in range(N-1):
    if a==0:
        break
    elif a==1:
        ans+=(N-1-i)
        break
    elif a%2==0:
        a//=2
        ans+=a
    else:
        a = a//2+1
        ans+=a

print(ans)