n, s, k = map(int, input().split())
MOD = 10 ** 9 + 7


dp = [[[0] * (s + 1) for i in range(s + 1)] for i in range(n)]
for ki in range(s + 1):
    dp[0][ki][ki] = 1

for i in range(n - 1):
    ru = [[0] * (s + 1) for i in range(s + 1)]
    for si in range(s + 1):
        for sj in range(s):
            ru[si][sj + 1] = ru[si][sj] + dp[i][si][sj]
    for si in range(s + 1):
        for ki2 in range(k, s + 1):
            if si + ki2 < s + 1:
                dp[i + 1][si + ki2][ki2] += ru[si][ki2 + 1 - k]
                dp[i + 1][si + ki2][ki2] %= MOD
            else:
                break

print(sum(dp[-1][-1]) % MOD)