#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, d, k;
  cin >> n >> k >> d;
  vector<vector<long long> > dp(2, vector<long long>(n + 1, 0));
  dp[0][0] = 1;
  dp[1][0] = 1;
  for (int i = 0; i <= n; i++) {
    if (dp[0][i] == 0) continue;
    for (int j = 1; j < d; j++) {
      if (i + j > n) break;
      dp[0][i + j] = (dp[0][i + j] + dp[0][i]) % 1000000007;
    }
  }
  for (int i = 0; i <= n; i++) {
    if (dp[1][i] == 0) continue;
    for (int j = 1; j <= k; j++) {
      if (i + j > n) break;
      dp[1][i + j] = (dp[1][i + j] + dp[1][i]) % 1000000007;
    }
  }
  long long ans = 0;
  for (int i = 0; i <= n; i++) {
    if (i + d > n) break;
    for (int j = d; j <= k; j++) {
      if (i + j > n) break;
      ans = (ans + dp[0][i] * dp[1][n - j - i]) % 1000000007;
    }
  }
  cout << ans;
  return 0;
}
