#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i ++)
using namespace std;
using ll = long long;
using PL = pair<ll,ll>;
using P = pair<int,int>;
constexpr int INF = 1000000000;
constexpr long long HINF = 1000000000000000;
constexpr long long MOD = 1000000007;// = 998244353;
constexpr double EPS = 1e-4;
constexpr double PI = 3.14159265358979;



template<int Modulus> 
struct ModInt {
    long long x;
    ModInt(long long x = 0) :x((x%Modulus + Modulus)%Modulus) {}
    constexpr ModInt &operator+=(const ModInt a) {if ((x += a.x) >= Modulus) x -= Modulus; return *this;}
    constexpr ModInt &operator-=(const ModInt a) {if ((x += Modulus - a.x) >= Modulus) x -= Modulus; return *this;}
    constexpr ModInt &operator*=(const ModInt a) {(x *= a.x) %= Modulus; return *this;}
    constexpr ModInt &operator/=(const ModInt a) {return *this *= a.inverse();}

    constexpr ModInt operator+(const ModInt a) const {return ModInt(*this) += a.x;}
    constexpr ModInt operator-(const ModInt a) const {return ModInt(*this) -= a.x;}
    constexpr ModInt operator*(const ModInt a) const {return ModInt(*this) *= a.x;}
    constexpr ModInt operator/(const ModInt a) const {return ModInt(*this) /= a.x;}
    
    friend constexpr ostream& operator<<(ostream& os,const ModInt<Modulus>& a) {return os << a.x;}
    friend constexpr istream& operator>>(istream& is,ModInt<Modulus>& a) {return is >> a.x;}
    
    ModInt inverse() const {// x ^ (-1) 
        long long a = x,b = Modulus,p = 1,q = 0;
        while (b) {long long d = a/b; a -= d*b; swap(a,b); p -= d*q; swap(p,q);}
        return ModInt(p);
    }
    ModInt pow(long long N) {// x ^ N 
        ModInt a = 1;
        while (N) {
            if (N&1) a *= *this;
            *this *= *this;
            N >>= 1;
        }
        return a;
    }
};

using mint = ModInt<1000000007>;
mint dp[105][2005];

int main() {
    int N,S,K; cin >> N >> S >> K;
    rep(i,N) S -= i*K;
    rep(i,N + 1) dp[i][0] = 1;
    rep(i,N)rep(j,S) {
        dp[i + 1][j + 1] = dp[i][j + 1];
        if (j - i >= 0) dp[i + 1][j + 1] += dp[i + 1][j - i];
    }
    cout << dp[N][S] << '\n';
    return 0;
}