# まず実験するか
from itertools import permutations

count = [[0]*(21) for i in range(21)]

for N in range(2, 5):
    for combo in permutations(range(1, N+1), N):
        #print(combo)
        temp = 0
        for j in range(1, N):
            if combo[j]-combo[j-1] < 0:
                temp += 1
        if temp == 1:
            count[N][20-N+combo[0]] += 1

for N in range(5, 21):
    temp = 0
    for j in range(20, -1, -1):
        count[N][j] = 2**temp
        temp += 1
        if temp == N:
            count[N][j] = sum(count[N-1])
            break

n, k = map(int, input().split())
ans = count[n][20-n+k]
print(ans)