#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
int dp[100][2];
int main() {
  int n, k, d;
  cin >> n;
  cin >> k;
  cin >> d;
  dp[0][0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= min(i, k); j++) {
      if (j < d) {
        dp[i][0] = dp[i][0] + dp[i - j][0];
        dp[i][1] = dp[i][1] + dp[i - j][1];
      } else {
        dp[i][1] = dp[i][1] + (dp[i - j][0] + dp[i - j][1]) % MOD;
      }
      dp[i][0] = dp[i][0] % MOD;
      dp[i][1] = dp[i][1] % MOD;
    }
  }
  cout << dp[n][1] << "\n";
  return 0;
}
