#include #include #include #include #include #include #include using namespace std; #define rep(i,x) for(ll i = 0; i < (ll)(x); i++) #define rrep(i,x) for(ll i = (ll)(x)-1;0 <= i; i--) #define reps(i,x) for(ll i = 1; i < (ll)(x)+1; i++) #define rreps(i,x) for(ll i = (ll)(x); 1 <= i; i--) #define debug(x) cerr << #x << ": " << (x) << "\n"; #define all(x) (x).begin(), (x).end() typedef long long ll; typedef long double ld; typedef pair P; typedef pair Pll; typedef vector vl; typedef vector> vvl; typedef vector>> vvvl; const ll INF = numeric_limits::max()/4; const int n_max = 1e5+10; template class modint { using i64 = int_fast64_t; public: i64 a; constexpr modint(const i64 x = 0) noexcept { this -> a = x % Modulus; if(a < 0){ a += Modulus; } } // constexpr i64 &value() const noexcept {return a;} constexpr const i64 &value() const noexcept {return a;} constexpr modint operator+(const modint rhs) const noexcept { return modint(*this) += rhs; } constexpr modint operator-(const modint rhs) const noexcept { return modint(*this) -= rhs; } constexpr modint operator*(const modint rhs) const noexcept { return modint(*this) *= rhs; } constexpr modint operator/(const modint rhs) const noexcept { return modint(*this) /= rhs; } constexpr modint &operator+=(const modint rhs) noexcept { a += rhs.a; if(a >= Modulus) { a -= Modulus; } return *this; } constexpr modint &operator-=(const modint rhs) noexcept { if(a < rhs.a) { a += Modulus; } a -= rhs.a; return *this; } constexpr modint &operator*=(const modint rhs) noexcept { a = a * rhs.a % Modulus; return *this; } constexpr modint &operator/=(modint rhs) noexcept { i64 a_ = rhs.a, b = Modulus, u = 1, v = 0; while(b){ i64 t = a_/b; a_ -= t * b; swap(a_,b); u -= t * v; swap(u,v); } a = a * u % Modulus; if(a < 0) a += Modulus; return *this; } // 自前実装 constexpr bool operator==(const modint rhs) noexcept { return a == rhs.a; } constexpr bool operator!=(const modint rhs) noexcept { return a != rhs.a; } constexpr bool operator>(const modint rhs) noexcept { return a > rhs.a; } constexpr bool operator>=(const modint rhs) noexcept { return a >= rhs.a; } constexpr bool operator<(const modint rhs) noexcept { return a < rhs.a; } constexpr bool operator<=(const modint rhs) noexcept { return a <= rhs.a; } constexpr modint& operator++() noexcept { return (*this) += modint(1); } constexpr modint operator++(int) { modint tmp(*this); operator++(); return tmp; } constexpr modint& operator--() noexcept { return (*this) -= modint(1); } constexpr modint operator--(int) { modint tmp(*this); operator--(); return tmp; } template friend constexpr modint modpow(modint &mt, T n) noexcept { if(n < 0){ modint t = (modint(1) / mt); return modpow(t, -n); } modint res = 1; while(n){ if(n & 1)res *= mt; mt *= mt; n /= 2; } return res; } }; const ll MOD = 1e9+7; using mint = modint; // 標準入出力対応 std::ostream &operator<<(std::ostream &out, const modint &m) { out << m.a; return out; } std::istream &operator>>(std::istream &in, modint &m) { ll a; in >> a; m = mint(a); return in; } int main(){ ll n,d,k; cin >> n >> d >> k; mint a = 0; mint dp[2][k] = {}; dp[0][0] = 1; rep(i,n){ vector sum(k+1, 0); rep(j,k)sum[j+1] = sum[j] + dp[i & 1][j]; rep(j,k+1){ dp[(i+1) & 1][j] = sum[j] - sum[max(0LL,j-d)]; } } cout << dp[n & 1][k] << endl; }