#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using ll = long long;
#define rep(i, n) for(int  i = 0; i < (n); ++i)
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
const long long INF = 1LL << 60;
using Graph = vector<vector<int>>;
int gcd(int a, int b){
    if(b == 0) return a;  
    else return gcd(b, a%b);
}
struct Compare {
    bool operator()(const pair<ll, int>& a, const pair<ll, int>& b) {
        return a.first > b.first;  
    }
};

ll mod = 1e9 + 7;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,s,k; cin >> n >> s >> k;
    vector<vector<ll>> dp(n+1, vector<ll>(s+1, 0));
    dp[0][0] = 1;
    for(int i=0;i<=n;i++){
        rep(j,s+1){
            if(j - k*(n-i) >= 0 && i > 0) dp[i][j] += dp[i-1][j-k*(n-i)];
            dp[i][j] %= mod;
            if(j - (n-i) >= 0) dp[i][j] += dp[i][j-(n-i)];
            dp[i][j] %= mod;
        }
    }
    cout << dp[n-1][s] << endl;
    return 0;
}