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#include <bits/stdc++.h>
#include "message.h"
#include "kanapka.h"

using namespace std;

typedef long long LL;

template<typename TH>
void debug_vars(const char* data, TH head){
    cerr << data << "=" << head << "\n";
}

template<typename TH, typename... TA>
void debug_vars(const char* data, TH head, TA... tail){
    while(*data != ',') cerr << *data++;
    cerr << "=" << head << ",";
    debug_vars(data+1, tail...);
}

#ifdef LOCAL
#define debug(...) debug_vars(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (__VA_ARGS__)
#endif

/////////////////////////////////////////////////////////


const int SendAfter = 300;

struct Sender {
    enum FieldType { FLD_CHAR, FLD_INT, FLD_LL };
    struct field {
        FieldType type;
        union { char ch; int n; LL l; };
    };
    struct Submitter {};

    vector<field> toSend;
    int dest;
    int cap;

    Sender() : dest(-10000), cap(SendAfter) {}
    Sender(int dst){
        dest = dst;
        cap = SendAfter;
        toSend.clear();
    }
    ~Sender(){
        if(toSend.size() > 0) submit();
    }

    int capacity() const { return cap; }
    void capacity(int newCapacity) { cap = newCapacity; }
    
    void submit(){
        if(toSend.size() == 0) return;
        PutInt(dest, (int)toSend.size());
        for(auto& f : toSend){
            switch(f.type){
                case FLD_CHAR: PutChar(dest, f.ch); break;
                case FLD_INT:  PutInt(dest, f.n); break;
                case FLD_LL:   PutLL(dest, f.l); break;
                default:       assert(false);
            }
        }
        Send(dest);
        toSend.clear();
    }

    void add_field(field f){
        assert(dest >= 0);
        toSend.push_back(f);
        if(toSend.size() >= cap) submit();
    }

    friend Sender& operator<<(Sender& snd, char ch){
        field f; f.type = FLD_CHAR; f.ch = ch; snd.add_field(f); return snd;
    }
    friend Sender& operator<<(Sender& snd, int n){
        field f; f.type = FLD_INT; f.n = n; snd.add_field(f); return snd;
    }
    friend Sender& operator<<(Sender& snd, LL l){
        field f; f.type = FLD_LL; f.l = l; snd.add_field(f); return snd;
    }
    friend Sender& operator<<(Sender& snd, Sender::Submitter){
        snd.submit(); return snd;
    }
};
Sender::Submitter submit;


struct Receiver {
    int numEnqueued;
    int node;

    Receiver() : node(-10000) {}
    Receiver(int nod) : node(nod), numEnqueued(0) {}

    void try_fetch(){
        assert(node >= -1);
        assert(numEnqueued >= 0);
        if(numEnqueued > 0){ numEnqueued--; return; }
        Receive(node);
        numEnqueued = GetInt(node);
    }

    char read_char(){ try_fetch(); return GetChar(node); }
    int read_int(){ try_fetch(); return GetInt(node); }
    LL read_ll(){ try_fetch(); return GetLL(node); }

    friend Receiver& operator>>(Receiver& recv, char& ch){
        ch = recv.read_char(); return recv;
    }
    friend Receiver& operator>>(Receiver& recv, int& n){
        n = recv.read_int(); return recv;
    }
    friend Receiver& operator>>(Receiver& recv, LL& l){
        l = recv.read_ll(); return recv;
    }
};



struct SandwichInfo {
    LL maxPref, maxSuf, maxPrefSuf, sum;

    SandwichInfo() : maxPref(0), maxSuf(0), maxPrefSuf(0), sum(0) {}
    explicit SandwichInfo(LL value){
        maxPref = maxSuf = maxPrefSuf = max(value, 0LL);
        sum = value;
    }
    SandwichInfo(LL sMaxPref, LL sMaxSuf, LL sMaxPrefSuf, LL sSum)
        : maxPref(sMaxPref),
          maxSuf(sMaxSuf),
          maxPrefSuf(sMaxPrefSuf),
          sum(sSum) {}

    SandwichInfo operator+(const SandwichInfo other) const {
        SandwichInfo result;
        result.maxPref    = max(maxPref, sum+other.maxPref);
        result.maxSuf     = max(other.maxSuf, other.sum+maxSuf);
        result.maxPrefSuf = max(max(sum + other.maxPrefSuf,
                                    other.sum + maxPrefSuf),
                                maxPref + other.maxSuf);
        result.sum        = sum + other.sum;
        return result;
    }

    friend Sender& operator<<(Sender& snd, const SandwichInfo info){
        snd << info.maxPref << info.maxSuf << info.maxPrefSuf << info.sum;
        return snd;
    }
    friend Receiver& operator>>(Receiver& recv, SandwichInfo& info){
        recv >> info.maxPref >> info.maxSuf >> info.maxPrefSuf >> info.sum;
        return recv;
    }
};


SandwichInfo fetch_info(int id, int N){
    int nNodes = min(N, NumberOfNodes());
    int left   = (LL)N * id / nNodes,
        right  = (LL)N * (id+1) / nNodes;

    SandwichInfo info;
    for(int i = left; i < right; i++) info = info + SandwichInfo(GetTaste(i));
    return info;
}


int main(){
    int id = MyNodeId(), N = GetN();
    if(id >= N) return 0;
    int nNodes = min(N, NumberOfNodes());
    SandwichInfo info = fetch_info(id, N);

    if(id > 0){
        // submit to 0
        Sender snd(0);
        snd << info << submit;
    } else {
        // receive everything
        for(int node = 1; node < nNodes; node++){
            Receiver recv(node);
            SandwichInfo nxt;
            recv >> nxt;
            info = info + nxt;
        }
        cout << info.maxPrefSuf << endl;
    }
}