#include <bits/stdc++.h>
#include <atcoder/modint>
using namespace std;
using namespace atcoder;
using ll = long long;
using mint = modint1000000007;

template<typename T> vector<vector<T>> Partition(int N) {
  vector<vector<T>> r(N + 1, vector<T>(101, 0));
  for(int i = 0; i <= 100; i++) { r[0][i] = 1; }
  for(int i = 1; i <= N; i++) {
    for(int j = 1; j <= 100; j++) { r[i][j] = r[i][j - 1] + (i - j >= 0 ? r[i - j][j] : 0); }
  }
  return r;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  ll N, S, K;
  cin >> N >> S >> K;

  S -= K * N * (N - 1) / 2;

  if(S < 0) {
    cout << 0 << "\n";
    return 0;
  }

  auto p = Partition<mint>(S);
  cout << p[S][N].val() << "\n";
}