#include <bits/stdc++.h>
using namespace std;
long long int n, k, d, dp[110][2], i, j;
int main() {
  ios::sync_with_stdio(0);
  cin >> n >> k >> d;
  for (i = 0; i < d; i++) dp[i][0] = 0;
  dp[0][1] = 1;
  for (i = 1; i < d; i++) {
    dp[i][1] = 0;
    for (j = i - 1; j >= 0; j--) {
      dp[i][1] = (dp[i][1] + dp[j][1]) % 1000000007;
    }
  }
  for (i = d; i <= n; i++) {
    dp[i][0] = 0;
    dp[i][1] = 0;
    for (j = 1; j < d; j++) {
      dp[i][0] = (dp[i][0] + dp[i - j][0]) % 1000000007;
      dp[i][1] = (dp[i][1] + dp[i - j][1]) % 1000000007;
    }
    for (; j <= k && i - j >= 0; j++) {
      dp[i][0] = (dp[i][0] + dp[i - j][1]) % 1000000007;
      dp[i][1] = (dp[i][1] + dp[i - j][1]) % 1000000007;
    }
  }
  cout << dp[n][0];
  return 0;
}
