"""

奇数なら, +1 して//2

"""

import sys
from sys import stdin
import heapq

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

NN,MM = N,M

ans = 0
while MM > 1 and NN > 0:

    ans += MM
    NN -= 1
    MM = (MM+1)//2

if NN >= 0 and MM == 1:
    print (ans + NN)
    sys.exit()

print (2**N-1)