#include <bits/stdc++.h>
using namespace std;
int n, m, d;
long long f[101][101][2], ans = 0, mod = 1000000007;
int main() {
  scanf("%d%d%d", &n, &m, &d);
  f[0][0][0] = 1;
  for (int i = 1; i <= n; i++)
    for (int j = i; j <= min(n, m * i); j++) {
      for (int k = 1; k < d && k <= j; k++)
        f[i][j][0] = (f[i][j][0] + f[i - 1][j - k][0]) % mod;
      for (int k = 1; k <= m && k <= j; k++)
        f[i][j][1] = (f[i][j][1] + f[i - 1][j - k][1]) % mod;
      for (int k = d; k <= m && k <= j; k++)
        f[i][j][1] = (f[i][j][1] + f[i - 1][j - k][0]) % mod;
    }
  for (int i = 1; i <= n; i++) ans = (ans + f[i][n][1]) % mod;
  printf("%I64d\n", ans);
  return 0;
}
