#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;
const int MOD7 = ( int ) 1e9 + 7;

int N, S, K;

void init(){
  cin >> N >> S >> K;
}

vvi dp;

void preprocess(){
  dp = vvi( N + 1, vi( S + 1 ) );
  dp[ 1 ][ 0 ] = 1;
  for( int i = 0; i <= N; ++i )
    for( int j = 0; j <= S; ++j ){
      if( i + 1 <= N and j + ( N - i ) * K <= S )
        ( dp[ i + 1 ][ j + ( N - i ) * K ] += dp[ i ][ j ] ) %= MOD7;
      if( j + ( N - i + 1 ) <= S )
        ( dp[ i ][ j + ( N - i + 1 ) ] += dp[ i ][ j ] ) %= MOD7;
      // cout << "dp[ " << i << " ][ " << j << " ] = " << dp[ i ][ j ] << endl;
    }
}

void solve(){
  cout << dp[ N ][ S ] << endl;
}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}