E - Grass

/*#include <bits/stdc++.h>
using namespace std;

#define int long long
const int N = 1e3 + 5;
const int mod = 1e18 + 7;
const int INF = 1e18;
int dp[N];

signed main()
{
    int n , k;
    cin >> n >> k;
    dp[1] = 1;
    int sum = 1;
    for(int i = 2; i <= n; i++){
        dp[i] = sum;
        if((i - k) >= 0)
            sum -= dp[i - k];
        sum += dp[i];
        sum += mod;
        sum %= mod;
    }
    cout << dp[n] << endl;
}*/

/*
#include <bits/stdc++.h>
using namespace std;

#define int long long
const int N = 1e3 + 5;
const int mod = 1e9 + 7;
const int INF = 1e18;
int dp[N];

signed main()
{
    int n , k;
    cin >> n >> k;
    dp[1] = 1;
    for(int i = 2; i <= n; i++){
        for(int j = (i - 1); j >= max(i - k , 0LL); j--){
            dp[i] += dp[j];
        }
    }
    cout << dp[n] << endl;
}
*/