#include <algorithm>
#include <climits>
#include <deque>
#include <iostream>
#include <queue>
#include <random>
#include <string>
#include <vector>
using namespace std;
 
typedef long long ll;
typedef pair<int, int> i_i;
struct edge { int i, v, z; };

int MOD = 1000000007;

int main() {
	int N, S, K; cin >> N >> S >> K;
	vector<vector<int> > dp(N + 1, vector<int>(S + 1));
	dp[N][0] = 1;
	for (int i = N; i > 0; i--)
		for (int j = 0; j <= S; j++) {
			if (j + i <= S) dp[i][j + i] = (dp[i][j + i] + dp[i][j]) % MOD;
			if (j + (i - 1) * K <= S) dp[i - 1][j + (i - 1) * K] = (dp[i - 1][j + (i - 1) * K] + dp[i][j]) % MOD;
		}
	cout << dp[0][S] << endl;
}