#include <iostream>
#include <vector>
#include <algorithm>
#include <tuple>
#include <queue>

using namespace std;

using ll = long long;
using pii = pair<int, int>;	using pll = pair<ll, ll>;	using pil = pair<int, ll>;	using pli = pair<ll, int>;
using vi = vector<int>;		using vvi = vector<vi>;		using vvvi = vector<vvi>;
using vll = vector<ll>;		using vvll = vector<vll>;	using vvvll = vector<vvll>;
using vb = vector<bool>;	using vvb = vector<vb>;		using vvvb = vector<vvb>;
template <class T> using pqr = priority_queue<T, vector<T>, greater<T>>;

const ll INFL = (ll)1e18;	const int INF = (int)1e9;
const int MOD = 1000000007;

template <class T> inline bool chmax(T& M, const T& x) { if (M < x) { M = x; return true; } return false; } // 最大値を更新（更新されたら true を返す）
template <class T> inline bool chmin(T& m, const T& x) { if (m > x) { m = x; return true; } return false; } // 最小値を更新（更新されたら true を返す）


int main() {
	int N, S, K;
	cin >> N >> S >> K;

	vvi DP(S + 1, vi(N + 1, 0));
	for (int i = 0; i <= S; i++)
		DP[i][1] = 1;

	for (int i = 0; i <= S; i++) {
		for (int j = 2; j <= N; j++) {
			if (i - j >= 0)
				DP[i][j] += DP[i - j][j];
			if (i - K * (j - 1) >= 0)
				DP[i][j] += DP[i - K * (j - 1)][j - 1];
			DP[i][j] %= MOD;
		}
	}

	cout << DP[S][N] << endl;


	return 0;
}