import java.util.*;

public class Main {
    static final int MOD = 1000000007;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int s = sc.nextInt();
        int k = sc.nextInt();
        int[][] dp = new int[n][s + 1];
        for (int i = 0; i * n <= s; i++) {
            dp[0][i * n]++;
        }
        for (int i = 1; i < n; i++) {
            for (int j = 0; j <= s; j++) {
                if (dp[i - 1][j] == 0) {
                    continue;
                }
                for (int a = k; j + a * (n - i) <= s; a++) {
                    dp[i][j + a * (n - i)] += dp[i - 1][j];
                    dp[i][j + a * (n - i)] %= MOD;
                }
            }
        }
        System.out.println(dp[n - 1][s]);
    }
}