#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;
#define MOD 1000000007

ostream& operator << (ostream& os, vector<long long>& v){
	for(int i=0; i<v.size(); i++){
		os << v[i] << " ";
	}
	return os;
}

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

	vector<long long> dp(s+1, 0);
	for(int i=0; i<=s; i++){
		if(s < i*n) break;
		dp[s - i*n] = 1;
	}
	
	//cerr << dp << endl;

	for(int i=1; i<n; i++){
		vector<long long> dp_(s+1, 0);
		for(int j=0; j<=s; j++){
			if(j - k*(n-i) < 0) continue;
			long long& v =  dp_[ j-k*(n-i) ];
			v += dp[j];
			if( v >= MOD ) v-=MOD;
		}
		vector<bool> visit(s+1, false);
		for(int j=s; j>=0; j--){
			int pos = j;
			while(pos >= 0 && visit[pos] == false){
				visit[pos] = true;
				if( pos - (n-i) < 0) continue;
				
				dp_[pos - (n-i)] += dp_[pos];
				if(dp_[pos - (n-i)] >= MOD) dp_[pos - (n-i)] -= MOD;
			}
		}
		swap(dp, dp_);
	}

	cout << dp[0] << endl;

	return 0;
}