n, m = map(int,input().split())
if m == 1:
    print(n)
    exit()
maxi = 0
for v in range(m + 1000):
    if 2 ** (v + 1) >= m:
        maxi = v + 1
        break
if maxi >= n:
    ans = 2 ** n - 1
    print(ans)
    exit()
now = 2 ** maxi - m
if now != 0:
    s = bin(now)[2:]
    ans = [2]
    for i in range(len(s)):
        if s[i] == '1':
            ans.append(2 * ans[-1] - 1)
        else:
            ans.append(2 * ans[-1])
    l = n - len(s)
    print(sum(ans) + l - 1)
else:
    ans1 = 2 ** (maxi + 1) - 1
    ans2 = n - maxi - 1
    print(ans1 + ans2)