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