#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;
constexpr i64 MOD = 1e9 + 7;
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("O3")

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cout.setf(ios::fixed);
    cout.precision(10);
    int n, s, k;
    cin >> n >> s >> k;

    const int maxS = s + 1;
    vvi dp(n + 1, vi(maxS));
    for (int i = k; i < maxS; i++) {
        dp[1][i] = 1;
    }

    for (int i = 2; i <= n; i++) {
        for (int j = 0; j < maxS; j++) {
            for (int d = k; d < maxS; d++) {
                int rem = j - d * i;
                if (rem >= 0) {
                    dp[i][j] += dp[i - 1][rem];
                    dp[i][j] %= MOD;
                } else {
                    break;
                }
            }
        }
    }

    i64 ans = 0;
    for (int i = 0; i < maxS; i++) {
        int rem = s - i * n;
        if (rem >= 0) {
            ans += dp[n - 1][rem];
            ans %= MOD;
        } else {
            break;
        }
    }
    cout << ans << endl;
}