#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines


# %%
import numpy as np
MOD = 10 ** 9 + 7

# %%
N, K = map(int, readline().split())

# %%
dp = np.zeros(K + 1, np.int64)
dp[0] = 1
for n in range(1, N + 1):
    if n <= K:
        dp[n:] -= dp[:-n]
    np.cumsum(dp, out=dp)
    dp %= MOD

# %%
answer = dp.sum() % MOD
print(answer)