import sys

dp =  [ [ [0 for _ in range(152)] for _ in range(302) ] for _ in range(302)]
mark = [ [ [0 for _ in range(152)] for _ in range(302) ] for _ in range(302)]
pas = 0
n = 0
d = 0

def f(id, a, de):
    if(id == n):
        return de == d and a == 0
    if(a > n//2):
        return 0
    if(mark[id][a][de] == pas):
        return dp[id][a][de]
    mark[id][a][de] = pas
    if(a):
        dp[id][a][de] = f(id + 1, a - 1, de) + f(id + 1, a + 1, max(de,a+1))
        return dp[id][a][de]

    dp[id][a][de] = f(id + 1, a + 1, max(de,a+1))
    return dp[id][a][de]


for q in sys.stdin:
    vet = q.split()
    n = int(vet[0])
    d = int(vet[1])
    pas += 1
    print ("%d"%f(0,0,0))