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#include <iostream>
#include <cstdio>
#include <string>
#include <sstream> 
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <ctime>
#include <cassert>

#include "kanapka.h"
#include "message.h"

using namespace std;
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define fi first
#define se second
#define vi vector<int>
#define vpii vector<pii>
#define SZ(x) ((int)(x.size()))
#define DBG cerr << "debug here" << endl;
#define DBGV(vari) cerr << #vari<< " = "<< (vari) <<endl;

using ll = long long;

const ll INF = 1e9+10;
const int MASTER = 0;

struct BlockResult {
    ll sum;
    ll min_prefix;
    ll min_suffix;
    ll min_sum;
};

int main()
{
    ios_base::sync_with_stdio(0);

    const ll id = MyNodeId();
    const ll n = GetN();
    const ll k = min(n, (ll)NumberOfNodes());

    //don't need such instances
    if (id >= k) return 0;

    const ll block_len = ceil(n / (double)k);
    const ll range_begin = id*block_len;
    const ll range_end = min(n-1, (id+1)*block_len-1);
    const ll range_len = range_end-range_begin+1;

    vector<ll> a(range_len);
    /* reading values in my range */
    for (int i = range_begin; i <= range_end; ++i) {
        a[i-range_begin] = GetTaste(i);
    }

    // computing local result

    // computing sum
    ll sum = 0;
    for (auto v : a) {
        sum += v;
    }

    // computing min_prefix
    ll min_prefix = 0;
    {
        ll cum_sum = 0;
        for (auto v : a) {
            cum_sum += v;
            min_prefix = min(min_prefix, cum_sum);
        }
    }

    // computing min_suffix
    ll min_suffix = 0;
    {
        ll cum_sum = 0;
        for (auto it = a.rbegin(); it != a.rend(); ++it) {
            cum_sum += *it;
            min_suffix = min(min_suffix, cum_sum);
        }
    }

    // computing min sum subsegment
    ll min_sum = 0;
    {
        ll min_ending_here = 0;
        for (auto v : a) {
            min_ending_here = min(min_ending_here + v, v);
            min_sum = min(min_sum, min_ending_here);
        }
    }

    // joining results
    PutLL(MASTER, sum);
    PutLL(MASTER, min_prefix);
    PutLL(MASTER, min_suffix);
    PutLL(MASTER, min_sum);
    Send(MASTER);

    if (id == MASTER) {
        vector<BlockResult> a(k);
        for (int sender_id = 0; sender_id < k; ++sender_id) {
            Receive(sender_id);
            BlockResult res;
            res.sum = GetLL(sender_id);
            res.min_prefix = GetLL(sender_id);
            res.min_suffix = GetLL(sender_id);
            res.min_sum = GetLL(sender_id);
            a[sender_id] = res;
        }
        ll total = 0;
        for (auto b : a) {
            total += b.sum;
        }
        ll min_sum = 0;

        // case 1: min_sum is inside a single block
        for (auto b : a) {
            min_sum = min(min_sum, b.min_sum);
        }
        // case 2: min_sum is spanned across multiple blocks
        /*
        for (int i = 0; i < k; ++i) {
            ll sum_between = 0;
            for (int j = i+1; j < k; ++j) {
                ll min_here = a[i].min_suffix + sum_between + a[j].min_prefix;
                min_sum = min(min_sum, min_here);
                sum_between += a[j].sum;
            }
        }
        */
        for (int i = 0; i < k; ++i) {
            for (int j = i+1; j < k; ++j) {
                ll min_here = a[i].min_suffix;
                for (int x = i+1; x < j; ++x) {
                    min_here += a[x].sum;
                }
                min_here += a[j].min_prefix;
                min_sum = min(min_sum, min_here);
            }
        }
        cout << total - min_sum << endl;
    }

    return 0;
}