#include <algorithm>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <queue>
#include <set>
#include <tuple>
#include <vector>

using namespace std;

#define rep(i, n) for (int64_t i = 0; i < (n); i++)
#define irep(i, n) for (int64_t i = 0; i <= (n); i++)
#define rrep(i, n) for (int64_t i = (n)-1; i >= 0; i--)
#define rirep(i, n) for (int64_t i = n; i >= 0; i--)

const uint64_t MOD = 1'000'000'007L;

int64_t dp[20'001][101];

int main()
{
    int n, s, k;
    cin >> n >> s >> k;

    irep(i, s) irep(j, n)
    {
        if (j == 0) {
            dp[i][j] = i == 0 ? 1 : 0;
        } else {
            dp[i][j] = 0;
            if (i - j >= 0) {
                dp[i][j] += dp[i - j][j];
                dp[i][j] %= MOD;
            }
            if (i - k * (j - 1) >= 0) {
                dp[i][j] += dp[i - k * (j - 1)][j - 1];
                dp[i][j] %= MOD;
            }
        }
    }
    cout << dp[s][n] << endl;

    return 0;
}