#include using namespace std; #define BOUND 27182818284 #define MAT 2 typedef long long ll; typedef long long int lli; typedef pair P; ll MOD = 1000000007; const ll INF = (1ll << 60); const int INFint = (1 << 30); #define rep(i, n) for(int i = 0; i < (int)(n); i++) #define repi(i, a, b) for(int i=int(a);i bool umax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; } template bool umin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; } // gcd template T gcd(T a, T b) { if (a == 0) return b; return gcd(b % a, a); } ll findGCD(vector arr) { ll result = arr[0]; for (auto a : arr) { result = gcd(a, result); } return result; } template T getlcm(T m, T n) { // 引数に0がある場合は0を返す if ((0 == m) || (0 == n)) return 0; return ((m / gcd(m, n)) * n); // lcm = m * n / gcd(m,n) } template void Fill(A (&array)[N], const T &val) { fill((T *) array, (T *) (array + N), val); } // v.front() = -BOUND; // v.back() = BOUND; //struct edge{ // int cost, to; // // edge(int in_cost, int in_to){ // cost=in_cost; // to=in_to; // } // bool operator<(const edge &a) const // { // return cost > a.cost; // } //}; ll euler_phi(ll n) { ll ret = n; for (ll i = 2; i * i <= n; i++) { if (n % i == 0) { ret -= ret / i; while (n % i == 0) n /= i; } } if (n > 1) ret -= ret / n; return ret; } class Combination { long long powmod(long long a, long long p) { long long ans = 1LL; long long mul = a; while (p > 0) { if ((p & 1) == 1) { ans = (ans * mul) % mod; } mul = (mul * mul) % mod; p >>= 1; } return ans; } public: int N; long long mod; vector fact; vector revfact; Combination(int n, long long m) : N(n), mod(m), fact(n + 1), revfact(n + 1) { fact[0] = 1; for (int i = 1; i <= N; i++) { fact[i] = fact[i - 1] * i; fact[i] %= mod; } revfact[N] = powmod(fact[N], mod - 2); for (int i = N - 1; i >= 0; i--) { revfact[i] = revfact[i + 1] * (i + 1) % mod; } } long long getCombination(int a, int b) { if (a < 0 || b < 0) return 0; if (b > a)return 0; return (fact[a] * revfact[b]) % mod * revfact[a - b] % mod; } }; struct mint { const int mod = 1000000007; ll x; // typedef long long ll; mint(ll x = 0) : x((x % mod + mod) % mod) {} mint &operator+=(const mint a) { if ((x += a.x) >= mod) x -= mod; return *this; } mint &operator-=(const mint a) { if ((x += mod - a.x) >= mod) x -= mod; return *this; } mint &operator*=(const mint a) { (x *= a.x) %= mod; return *this; } mint operator+(const mint a) const { mint res(*this); return res += a; } mint operator-(const mint a) const { mint res(*this); return res -= a; } mint operator*(const mint a) const { mint res(*this); return res *= a; } mint pow(ll t) const { if (!t) return 1; mint a = pow(t >> 1); a *= a; if (t & 1) a *= *this; return a; } // for prime mod mint inv() const { return pow(mod - 2); } mint &operator/=(const mint a) { return (*this) *= a.inv(); } mint operator/(const mint a) const { mint res(*this); return res /= a; } }; struct UnionFind { int n, cnt; vector par, rank, sz; UnionFind(int n) : n(n), cnt(n), par(n), rank(n), sz(n, 1) { iota(par.begin(), par.end(), 0); } int find(int x) { if (x == par[x]) return x; return par[x] = find(par[x]); } bool same(int x, int y) { return find(x) == find(y); } int size(int x) { return sz[find(x)]; } void unite(int x, int y) { x = find(x), y = find(y); if (x == y) return; if (rank[x] < rank[y]) { par[x] = y; sz[y] += sz[x]; } else { par[y] = x; sz[x] += sz[y]; if (rank[x] == rank[y]) { rank[x]++; } } cnt--; } }; const string Yes = "Yes"; const string YES = "YES"; const string No = "No"; const string NO = "NO"; long long modpow(long long a, long long n, long long mod) { long long res = 1; while (n > 0) { if (n & 1) res = res * a % mod; a = a * a % mod; n >>= 1; } return res; } template struct SegmentTree { using F = function; int sz; vector seg; const F f; const Monoid M1; SegmentTree(int n, const F f, const Monoid &M1) : f(f), M1(M1) { sz = 1; while (sz < n) sz <<= 1; seg.assign(2 * sz, M1); } void set(int k, const Monoid &x) { seg[k + sz] = x; } void build() { for (int k = sz - 1; k > 0; k--) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } void update(int k, const Monoid &x) { k += sz; seg[k] = x; while (k >>= 1) { seg[k] = f(seg[2 * k + 0], seg[2 * k + 1]); } } Monoid query(int a, int b) { Monoid L = M1, R = M1; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) L = f(L, seg[a++]); if (b & 1) R = f(seg[--b], R); } return f(L, R); } Monoid operator[](const int &k) const { return seg[k + sz]; } template int find_subtree(int a, const C &check, Monoid &M, bool type) { while (a < sz) { Monoid nxt = type ? f(seg[2 * a + type], M) : f(M, seg[2 * a + type]); if (check(nxt)) a = 2 * a + type; else M = nxt, a = 2 * a + 1 - type; } return a - sz; } template int find_first(int a, const C &check) { Monoid L = M1; if (a <= 0) { if (check(f(L, seg[1]))) return find_subtree(1, check, L, false); return -1; } int b = sz; for (a += sz, b += sz; a < b; a >>= 1, b >>= 1) { if (a & 1) { Monoid nxt = f(L, seg[a]); if (check(nxt)) return find_subtree(a, check, L, false); L = nxt; ++a; } } return -1; } template int find_last(int b, const C &check) { Monoid R = M1; if (b >= sz) { if (check(f(seg[1], R))) return find_subtree(1, check, R, true); return -1; } int a = sz; for (b += sz; a < b; a >>= 1, b >>= 1) { if (b & 1) { Monoid nxt = f(seg[--b], R); if (check(nxt)) return find_subtree(b, check, R, true); R = nxt; } } return -1; } }; ll stairs[310][310*310]; int main() { int N, d, K; cin >> N >> d >> K; Fill(stairs, 0LL); stairs[0][0]=1LL; // i回目の操作 for(int i=1; i<=N; i++){ // 前の合計をとっておく ll sum = 0; // j段目にたどり着く方法(i段目にはたどり着く・最大d*i段目) for(int j=i; j<=d*i; j++){ if(j>i*d) continue; if(j-d<=0){ sum += stairs[i-1][j-1]; sum%=MOD; }else{ sum += (stairs[i-1][j-1] - stairs[i-1][j-(d+1)]); sum%=MOD; } if(sum<0LL) sum += MOD; stairs[i][j] = sum; } } cout << stairs[N][K] << endl; return 0; }