#include "homecoming.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
const int N = (int)2e6 + 7;
ll pref[N], dp[N];
ll get(int l, int r) {
if (!l) return pref[r];
return pref[r] - pref[l - 1];
}
ll solve(int n, int k, int a[], int b[]) {
for (int i = 0; i < n + n - 2; i++) {
pref[i] = ((i != 0) ? pref[i - 1] : 0) + b[i % n];
}
ll cost;
for (int i = 0; i < n; i++) {
dp[i] = 0;
for (int j = 0; j < i; j++) {
cost = -get(max(j + k, i), i + k - 1) + a[i];
dp[i] = max(dp[i], dp[j] + cost);
}
dp[i] = max(dp[i], -get(i, i + k - 1) + a[i]);
}
for (int i = 1; i < n; i++) {
dp[i] = max(dp[i], dp[i - 1]);
}
return dp[n - 1];
}
