#include <bits/stdc++.h>
using namespace std;
const int N = 105, mod = 1e9 + 7;
int n, k, d;
int dp[N][2];
int go(int sum, bool found) {
  if (sum > n)
    return 0;
  else if (sum == n)
    return found;
  if (dp[sum][found] != -1) return dp[sum][found];
  dp[sum][found] = 0;
  for (int i = 1; i <= k; i++)
    dp[sum][found] += go(sum + i, (found || (i >= d))), dp[sum][found] %= mod;
  return dp[sum][found];
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> d;
  memset(dp, -1, sizeof dp);
  cout << go(0, false);
  return 0;
}
