#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(ll)(a);i<=(ll)(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(ll)(b);i>=(ll)(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
template<class T>
bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>
bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}

ll n,s,k;
ll dp[105][20005];
const ll mod=(ll)1e9+7;
ll f(ll i,ll sum){
    if(!i&&!sum)return 1LL;
    if(dp[i][sum]!=-1)return dp[i][sum];
    ll ret=0;
    if(i&&sum-k*(n-i)>=0)ret+=f(i-1,sum-k*(n-i));
    if(sum-(n-i)>=0)ret+=f(i,sum-(n-i));
    return dp[i][sum]=ret%mod;
}
void solve(){
    cin>>n>>s>>k;
    memset(dp,-1,sizeof(dp));
    cout<<f(n-1,s)<<endl;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    solve();
}