#include <bits/stdc++.h>
using namespace std;
long long mod = pow(10, 9) + 7;
int n, k, d;
long long dp[2][110];
int main() {
  scanf("%d%d%d", &n, &k, &d);
  dp[0][0] = dp[1][0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= k; j++) {
      if (i - j < 0)
        break;
      else {
        dp[0][i] += dp[0][i - j];
        dp[0][i] = dp[0][i] % mod;
      }
    }
    for (int k = 1; k <= d - 1; k++) {
      if (i - k < 0)
        break;
      else {
        dp[1][i] += dp[1][i - k];
        dp[1][i] = dp[1][i] % mod;
      }
    }
  }
  long long ans = ((dp[0][n] - dp[1][n]) % mod + mod) % mod;
  printf("%lld", ans);
  return 0;
}
