#include using namespace std; inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;} template inline string toString(T x) {ostringstream sout;sout< VI; typedef vector VVI; typedef vector VS; typedef pair P; typedef tuple tpl; #define ALL(a) (a).begin(),(a).end() #define RALL(a) (a).rbegin(), (a).rend() #define SORT(c) sort((c).begin(),(c).end()) #define REVERSE(c) reverse((c).begin(),(c).end()) #define LB(a,x) lower_bound((a).begin(), (a).end(), x) - (a).begin() #define UB(a,x) upper_bound((a).begin(), (a).end(), x) - (a).begin() #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define REP(i,n) FOR(i,0,n) #define RFOR(i,a,b) for(int i=(a)-1;i>=(b);--i) #define RREP(i,n) RFOR(i,n,0) #define en "\n" const double EPS = 1e-9; const double PI = acos(-1.0); const int INT_INF = 2147483647; const long long LL_INF = 1LL<<60; const long long MOD = 1000000007; #define CLR(a) memset((a), 0, sizeof(a)) #define dump(x) cerr << #x << " = " << (x) << endl; #define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template struct BIT{ private: public: using Func = function; int n; vector node; T init_v; Func func; BIT(vector a, Func _func, T _init_v) { n = a.size() + 1; init_v = _init_v; func = _func; node.resize(n, init_v); for(int i=1; i 0){ res = func(res, node[pos]); pos = pos & (pos-1); } return res; } }; template struct LazyBIT{ private: public: using Func = function; using MulInt = function; using Unary = function; BIT bit0, bit1; Func _add; MulInt _mul; Unary _inv; LazyBIT(vector a, Func add_func, MulInt mul_func, Unary inv, T _init_v) { int n = a.size(); _add = add_func; _mul = mul_func; _inv = inv; bit0 = BIT(a, add_func, _init_v); bit1 = BIT(vector(n,0), add_func, _init_v); } LazyBIT() {}; void init(vector a, Func add_func, MulInt mul_func, Unary inv, T _init_v) { int n = a.size(); _add = add_func; _mul = mul_func; _inv = inv; bit0 = BIT(a, add_func, _init_v); bit1 = BIT(vector(n,0), add_func, _init_v); } void add(int l, int r, T v) { bit0.add(l, _mul(_inv(v),l-1)); bit0.add(r+1, _mul(v,r)); bit1.add(l, v); bit1.add(r+1, _inv(v)); } T sum(int pos){ return _add(_mul(bit1.sum(pos),pos), bit0.sum(pos)); } }; struct mint { long long x; mint(long long x=0):x((x%MOD+MOD)%MOD){} mint operator-() const { return mint(-x);} 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(long long 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; } }; int main(void){ auto f = [](ll a, ll b){return (a+b)%MOD;}; auto g = [](ll a, ll b){return (a*b)%MOD;}; auto h = [](ll a){return a*(-1) + MOD;}; auto p = [](ll a, int b){return a*(ll)b;}; ll N,d,K; cin >> N >> d >> K; vector aa(K+1); REP(i,K+1) aa[i] = 0; LazyBIT bit[2]; REP(i,2) bit[i].init(aa,f,g,h,0); bit[0].add(1,1,1); REP(i,N){ int a,b; if(i%2 == 0){a = 0; b = 1;} else {a = 1; b = 0;} bit[b].init(aa,f,g,h,0); REP(j,K){ ll t = bit[a].sum(j+1) - bit[a].sum(j); if(t < 0) t += MOD; if(t > 0){ bit[b].add(j+2,min(K+1,j+d+1),t); } } } int a; if(N%2 == 0) a = 0; else a = 1; ll ans = bit[a].sum(K+1) - bit[a].sum(K); if(ans < 0) ans += MOD; cout << ans << en; return 0; }