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

now = 2 ** maxi - m


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)