# 公式解説の2つの数列に分ける方式

N, K = map(int, input().split())
count = [0]*N

for bit in range(1<<N):
    if bit == 0 or bit == pow(2, N)-1:
        continue
    
    first = []
    second = [a for a in range(N)]
    for shift in range(N):
        if bit>>shift&1 == 1:
            first.append(shift)
            second.remove(shift)
    if first[-1] > second[0]:
        count[first[0]] += 1
        
ans = count[K-1]
print(ans)