// https://yukicoder.me/problems/no/269
// status:
// tag: [分割数]
// ref: http://d.hatena.ne.jp/incognita/20110305/1299344781
// ref: http://drken1215.hatenablog.com/entry/2018/01/16/222843

#define SUBMIT
//#define DEBUG

#include <algorithm>
#include <cstring>
#include <iomanip>
#include <iostream>

using namespace std;
using ui64 = unsigned long long;
using i64 = long long;

const int M = 1000000000 + 7;
const int MAX_S = 20000;
const int MAX_N = 100;

// dp[N][S] SのN分割の総数
// dp[n][s] = dp[n][s - n] + dp[n - 1][s]   (s >= n)
// dp[n][s] = dp[n][s - 1]                  (otherwise)
int dp[MAX_N + 1][MAX_S + 1];
int N, S, K;

// 分割数
// nのm分割を求める
int solve_partition(int m, int n) {
    // init
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;

    // partition
    for (int i = 1; i <= m; ++i) {
        for (int j = 0; j <= n; ++j) {
            if (j - i >= 0) dp[i][j] = (dp[i - 1][j] + dp[i][j - i]) % M;
            else dp[i][j] = dp[i - 1][j] % M;
        }
    }

    return dp[m][n];
}

int main() {
#ifdef SUBMIT
    auto& stream = cin;
#else
    stringstream stream(R"(55 2555 1
)");
#endif
    stream >> N >> S >> K;
    for (int i = 0; i < N; ++i) S -= i * K;

    auto ans = solve_partition(N, S);
    cout << ans << endl;
    return 0;
}