#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double D;
typedef pair<ll,ll> P;
#define M 1000000007
#define F first
#define S second
#define PB push_back
#define INF 100000000000000000
ll n,s,k,dp[105][20005];
int main(void){
    cin>>n>>s>>k;
    ll p=n*(n-1)/2*k;
    if(s<p){
		cout<<0<<endl;
		return 0;
    }
    s-=p;
    dp[0][0]=1;
    for(ll i=1;i<=n;i++){
		ll o=n-i+1;
		for(ll j=0;j<o;j++)dp[i][j]=dp[i-1][j];
		for(ll j=o;j<=s;j++)dp[i][j]=(dp[i-1][j]+dp[i][j-o])%M;
	}
	cout<<dp[n][s]<<endl;
}