import sys
import math
sys.setrecursionlimit(67108864)
n,m=list (map(int,input ().split()))
def f(x,y):
    def a(x,y):
        return min(2**(x-1),y,)
    if x==1:
        return 1
    elif y==1:
        return x
    elif 2**(x-1)<=y:
        return 2**x-1
    elif y%2==0:
        yy=int(y/2)
        return f(x-1,yy)+a(x-1,yy)*2
    else:
        yy=math.ceil(y/2)
        return f(x-1,yy)+a(x-1,yy)*2-1
print(f(n,m))