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

#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define Rrep(i,n) for(int i=n-1;i>=0;i--)
#define Rrep1(i,n) for(int i=n;i>0;i--)
#define all(a) a.begin(),a.end()
using ll = long long;
using ull = unsigned long long;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
#define INF ((ll)2e15)
#define IINF ((int)1e9)
const double PI = 3.1415926535897932384626433832795028841971;
template<typename T>inline bool chmax(T& a, T b) { return ((a < b) ? (a = b, true) : (false)); }
template<typename T>inline bool chmin(T& a, T b) { return ((a > b) ? (a = b, true) : (false)); }
#define yesno(ans) cout<<((ans)?"Yes\n":"No\n")
bool eq(double a, double b) { return abs(a - b) < 0.0000001; }
const int di[4] = { 1,0,-1,0 };
const int dj[4] = { 0,-1,0,1 };

/*ACL
#include <atcoder/all>
using namespace atcoder;
//using mint = modint998244353;
using mint=modint1000000007;
using vm=vector<mint>;
using vvm=vector<vm>;
using vvvm=vector<vvm>;
//*/


int solve() {
   //分割数
    ll N,S,K;cin>>N>>S>>K;
    ll sub=K;
    K=0;
    rep(i,N)S-=K,K+=sub;
    if(S<0){
        cout<<0<<endl;
        return 0;
    }
    vvl dp(N+1,vl(S+1,0));
    dp[0][0]=1;
    //rep1(i,S)dp[0][i]=1;
    rep1(i,N)rep(j,S+1){
        if(j-i>=0)
        dp[i][j]+=dp[i][j-i];
        dp[i][j]+=dp[i-1][j];
        dp[i][j]%=1000000007;
    }
    cout<<dp[N][S]<<endl;
    return 0;
}
int main()
{
    std::cin.tie(0)->sync_with_stdio(0);
    int T = 1;
    //cin>>T;
    while (T--)
    {
        solve();
    }
    return 0;
}