#include <iostream>
#include <deque>
#include <vector>
#include <queue>
#include <set>
using namespace std;
int const NN=2e6+10;
long long dp[NN],pre[NN],val[NN];
long long sol(deque<int>a,deque<int>b,int k)
{
int n=a.size();
pre[0]=0;
for (int i=0;i<n;i++)
pre[i+1]=pre[i]+b[i];
dp[0]=a[0]-pre[k];
long long mx=dp[0],mx1=dp[0]+pre[k];
for (int i=1;i<n;i++)
{
long long sm=pre[min(n,i+k)]-pre[i];
dp[i]=max(mx,mx1-pre[i]);
dp[i]=dp[i]+a[i]-sm;
mx=max(mx,dp[i]);
mx1=max(mx1,dp[i]+pre[min(i+k,n)]);
}
return mx;
}
long long solve(int N, int K, int *A, int *B)
{
long long ans=0;
int n=N;
deque<int>a,b;
for (int i=0;i<n;i++)
a.push_back(A[i]),b.push_back(B[i]);
for (int i=0;i<n;i++)
{
ans=max(ans,sol(a,b,K));
a.push_back(a.front());
a.pop_front();
b.push_back(b.front());
b.pop_front();
}
return ans;
}
