#include <bits/stdc++.h>
using namespace std;
int getMaxSum(int arr[],int n,int k){
	int pre[n]={0};
	int suff[n+1]={0};
	for(int i=0;i<n;i++){
		pre[i]=pre[i]+arr[i];
	}
	for(int i=n-1;i>=0;i--){
		suff[i]=suff[i+1]+arr[i];
	}
	int sum;
	int maxi=suff[n-k];
	for(int i=0;i<k;i++){
		sum=0;
		sum=suff[n-k+i+1]+pre[i];
		maxi=max(sum,maxi);
	}
	return maxi;
 
}
 
int main() {
	// your code goes here
	int n;
	cin>>n;
	int k;
	cin>>k;
	int arr[n];
	for(int i=0;i<n;i++){
		cin>>arr[i];
	}
	cout<<"The maximum sum is:"<<getMaxSum(arr,n,k);
	return 0;
}

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