#include <bits/stdc++.h>
using namespace std;
const int N = 101;
const long long int mod = 1e9 + 7;
long long int dp[N][2];
int n, k, d;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k >> d;
  dp[0][0] = 1;
  dp[0][1] = 0;
  for (int v = 1; v <= n; v++) {
    for (int aresta = 1; aresta <= k; aresta++) {
      if (aresta > v) break;
      dp[v][0] += dp[v - aresta][0] % mod;
      if (aresta < d) {
        dp[v][1] += dp[v - aresta][1] % mod;
      } else {
        dp[v][1] += dp[v - aresta][0] % mod;
      }
      dp[v][0] %= mod;
      dp[v][1] %= mod;
    }
  }
  cout << dp[n][1] << endl;
  return 0;
}
