MOD = 10 ** 9 + 7

if __name__ == "__main__":
	n, d, k = map(int, input().split())
	
	dp = [0 for i in range(k + 1)]
	dp[0] = 1
	
	for _ in range(n):
		s = 0
		to = [0 for i in range(k + 1)]
		for i in range(k):
			s += dp[i]
			if i >= d:
				s -= dp[i - d]

			to[i + 1] = s
		dp = to

	print(dp[k])