n,k = map(int,input().split())
dp = [[0 for i in range(k+1)] for j in range(n+1)]
 
for i in range(1,n+1):
 
    dp[i][1] = 1
    if k >= 2:
        dp[i][2] = i//2
    if i <= k:
        dp[i][i] = 1
 
for i in range(4,n+1):
    for j in range(3,k+1):
        if i > j:
            dp[i][j] = dp[i-1][j-1] + dp[i-j][j]
 
print(dp[n][k])
 
/**************************************************************
	Problem: 1857
	User: admin
	Language: Python
	Result: Accepted
	Time:327 ms
	Memory:34480 kb
****************************************************************/