mod=10**9+7
def power(a, b):
    if(b == 0): return 1
    if(b % 2): return power(a, b - 1) * a % mod
    else:
        y = power(a, b // 2)
        return y * y % mod;
def rec(i,j):
    if i == 0:return 1
    if j%2 == 0:
        return (rec(i-1,j//2)+power(2,i-1)) %  mod
    else:
        return rec(i-1,j//2+1)
n,k=map(int,input().split())
print(rec(n,k))
Compilation message (stdout)
Compiling 'rack.py'...
=======
  adding: __main__.pyc (deflated 42%)
=======
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