#include <bits/stdc++.h>
using namespace std;
long long int mod = 1e9 + 7;
int dp[110][2];
int main() {
  int n, k, d;
  cin >> n >> k >> d;
  dp[0][0] = 1;
  dp[0][1] = 0;
  for (int i = 1; i <= n; i++) {
    dp[i][0] = dp[i][1] = 0;
    for (int j = 1; j <= min(i, k); j++) {
      if (j < d) {
        dp[i][0] = (dp[i][0] + dp[i - j][0]) % mod;
        dp[i][1] = (dp[i][1] + dp[i - j][1]) % mod;
      } else {
        dp[i][1] = (dp[i][1] + dp[i - j][0]) % mod;
        dp[i][1] = (dp[i][1] + dp[i - j][1]) % mod;
      }
    }
  }
  cout << dp[n][1] << "\n";
}
