#include <bits/stdc++.h>
using namespace std;
long long power(long long x, long long y) {
  long long res = 1;
  x = x % 1000000007;
  while (y > 0) {
    if (y & 1) {
      res = (res * x) % 1000000007;
    }
    y = y >> 1;
    x = (x * x) % 1000000007;
  }
  return res;
}
long long inv(long long x) { return power(x, 1000000007 - 2); }
long long dp[101];
long long solve(long long n, long long d) {
  if (n < 0 || d == 0) {
    return 0;
  } else if (n == 0) {
    return 1;
  } else if (dp[n] != -1) {
    return dp[n];
  }
  long long ways = 0;
  for (int i = 1; i <= d; i++) {
    ways = (ways + solve(n - i, d)) % 1000000007;
  }
  return dp[n] = ways;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, k, d;
  cin >> n >> k >> d;
  memset(dp, -1, sizeof(dp));
  long long ways1 = solve(n, k);
  memset(dp, -1, sizeof(dp));
  long long ways2 = solve(n, d - 1);
  cout << (ways1 - ways2 + 1000000007) % 1000000007;
  return 0;
}
