import sys
input = sys.stdin.readline
N, M = map(int, input().split())

m = M.bit_length() - 1
if N - 1 <= m:
  print(pow(2, N) - 1)
  exit(0)

res = 0
c = 0
while M > 1:
  res += M
  M += 1
  M >>= 1
  c += 1
  #print(M, c, res)
res += N - c
print(res)