//CF K-Tree
#include <iostream>
using namespace std;
#define MOD 1000000007
long long dp[104][2];
 
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    long n,k,d;
    cin>>n>>k>>d;
    for(int i=0; i<=100; i++)
        dp[i][0]=dp[i][1]=0;
    dp[0][0]=1;
    for(int s=1; s<=n; s++)
    {
        for(int i=(s-1); i>=(s-d+1) && i>=0; i--)
        {
            dp[s][0]=(dp[s][0]+dp[i][0])%MOD;
            dp[s][1]=(dp[s][1]+dp[i][1])%MOD;
        }
        for(int i=(s-d); i>=(s-k) && i>=0; i--)
            dp[s][1]=(dp[s][1]+dp[i][0]+dp[i][1])%MOD;
    }
    cout<<dp[n][1];
}
 
//You need to change the 'int' dp[104][2] to 'long long' dp[104][2]. This is because the temporary result stored in dp[i][k] is of data type int which overflows and hence wraps around to give negative results and hence wrong answer.

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

MyAzIDIK

3 3 2