#include<bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; i++)
#define repo(i, n) for(int i=1; i<=n; i++)
#define INF 1001001001

using namespace std;
using ull = unsigned long long;
using ll = long long;
using P = pair<int, int>;
const int mod = 1000000007;
const int NMAX = 105;
const int SMAX = 20010;

int main(){
  int n, s, k;
  cin >> n >> s >> k;
  vector<vector<ll> > dp(NMAX, vector<ll>(SMAX));
  for(int j=0; j*n<=s;j++){
    dp[0][j*n]=1;
  }
  for(int i=1; i<=n-1; i++){
    rep(j, s+1){
      if(j-(n-i)>=0){
        dp[i][j]+=dp[i][j-(n-i)];
        dp[i][j]%=mod;
      }
      if(j-k*(n-i)>=0){
        dp[i][j]+=dp[i-1][j-k*(n-i)];
        dp[i][j]%=mod;
      }
    }
  }
  cout << dp[n-1][s] << endl;
  return 0;
}