#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define sz(x) int(x.size())
using namespace std;

#define MAX_N 100
#define MAX_J 20000

// int N = 3;
// int S = 10;
// int K = 1;

int N, S, K;
int dp[MAX_N + 1][MAX_J + 1];
int main() {
    cin >> N >> S >> K;
    // P( S - (K + 2K + ... (N-1)K), N ) 問題
    // n = S - (K + 2K + ... (N-1)K)
    // m = N

    int max_j = S - (N - 1) * (K + (N - 1) * K) / 2;
    // cout << max_j << endl;
    // cout << (N - 1) * (K + (N - 1) * K) / 2 << endl;

    dp[0][0] = 1;
    for (int i = 1; i <= N; i++) {
        for (int j = 0; j <= max_j; j++) {
            if (j - i >= 0) {
                dp[i][j] = (dp[i - 1][j] + dp[i][j - i]) % 1000000007;
            } else {
                dp[i][j] = dp[i - 1][j];
            }
        }
    }
    printf("%d\n", dp[N][max_j]);
}