n, m = map(int,input().split())
maxi = 0
for i in range(1000):
    if 2 ** i >= m:
        maxi = i
        break
ans = 0
if maxi + 1 > n:
    ans = 2 ** n - 1
else:
    leng1 = maxi #2, 3, ...
    leng2 = n - leng1 #1, 1, ...
    now = 2 ** maxi - m
    a = [2]
    for i in range(leng1 - 2, -1, -1):
        if 1 & (now >> i):
            a.append(2 * a[-1] - 1)
        else:
            a.append(2 * a[-1])
    ans = sum(a[:leng1]) + leng2
print(ans)