#include <iostream>
#include <string>
#include <vector>
#include <numeric>

using namespace std;

using ll = long long;

template <class T>
using grid = vector<vector<T>>;

#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define REPD(i,n) for(ll i=n-1;i>=0;i--)
#define FOR(i,a,b) for(ll i=a;i<=(ll)(b);i++)
#define FORD(i,a,b) for(ll i=a;i>=(ll)(b);i--)

#define input(...) __VA_ARGS__; in(__VA_ARGS__)

void print() {
  std::cout << std::endl;
}

template <class Head, class... Tail>
void print(Head&& head, Tail&&... tail) {
  std::cout << head << " ";
  print(std::forward<Tail>(tail)...);
}

void in() { }

template <class Head, class... Tail>
void in(Head&& head, Tail&&... tail) {
  cin >> head;
  in(std::forward<Tail>(tail)...);
}

int main() {
  int input(N, d, K);

  vector<ll> dp(K + 1);
  REP(k, K + 1) { // n == 1 の時
    if (k <= 0) dp[k] = 0;
    else dp[k] = (int) k <= d;
  }

  vector<ll> cumsum(K + 1);
  REP(n, N - 1) { // [0, N - 1)
    FORD(k, K, 1) { // [K, 1]
      partial_sum(dp.begin(), dp.end(), cumsum.begin());
      dp[k] = cumsum[k - 1] - cumsum[max(1ll, k - d) - 1];
      // cumsum[a] - cumsum[b - 1] = sum(dp[b] ~ dp[a])
    }
  }

  print(dp[K]);
}