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#include <iostream>
#include <vector>
#include <algorithm>

#include "message.h"
#include "maklib.h"

class INodeRunner
{
public:
	virtual void Run() = 0;
};

struct AnalyseRequest
{
	long long beginIndex;
	
	long long endIndex;
};

struct AnalyseResult
{
	long long maxSum;
	
	long long maxSumFromBeginning;

	long long lastRangeSum;
};

struct NodeAnalyseResult
{
	int nodeId;
	AnalyseResult result;
};

class MergeNodeRunner: public INodeRunner
{
public:
	void Run()
	{
		int numberOfWorkingNodes = NumberOfNodes() - 1; //from 10 to 100
		long long tableSize = Size();
		_results.resize(numberOfWorkingNodes);

		SendAnalyseRequests(numberOfWorkingNodes, tableSize);
		
		for(int i = 0; i < numberOfWorkingNodes; ++i)
		{
			auto nodeResult = ReceiveNodeResult();
			_results[nodeResult.nodeId - 1] = nodeResult.result;
		}

		long long maxSum = GetMaxSum();

		std::cout << maxSum;
	}

private:

	long long GetMaxSum()
	{
		long long maxSum = _results[0].maxSum;
		long long lastRangeSum = 0;

		for(auto i = 1; i < _results.size(); ++i)
		{
			auto& res = _results[i];
			auto newSum = std::max(res.maxSum, res.maxSumFromBeginning + lastRangeSum);
			
			if(newSum > maxSum)
				maxSum = newSum;
			
			lastRangeSum = res.lastRangeSum;
		}

		return maxSum;
	}

	NodeAnalyseResult ReceiveNodeResult()
	{
		NodeAnalyseResult res;

		res.nodeId = Receive(-1);

		res.result.maxSum = GetLL(res.nodeId);
		res.result.maxSumFromBeginning = GetLL(res.nodeId);
		res.result.lastRangeSum = GetLL(res.nodeId);

		return res;
	}

	void SendAnalyseRequests(int numberOfNodes, long long tableSize)
	{
		int numberOfCalculateNodes = numberOfNodes;
		long long elementsPerNode = tableSize / (numberOfNodes - 1);

		long long currIdx = 0;
		int targetId = 1;

		while(tableSize > 0)
		{
			AnalyseRequest req;
			req.beginIndex = currIdx + 1;
			if(tableSize < elementsPerNode)
			{
				elementsPerNode = tableSize;
			}
			req.endIndex = currIdx + elementsPerNode;
			
			SendRequest(req, targetId);
			
			currIdx = currIdx + elementsPerNode;
			tableSize -= elementsPerNode;
			++targetId;
		}
	}

	void SendRequest(AnalyseRequest request, int targetId)
	{
		PutLL(targetId, request.beginIndex);
		PutLL(targetId, request.endIndex);

		Send(targetId);
	}

	std::vector<AnalyseResult> _results;
};

class SearcherNodeRunner: public INodeRunner
{
	static const int MergeNodeId = 0;

public:
	void Run()
	{
		auto req = ReceiveAnalyseRequest();

		auto resp = CalculateResult(req);

		SendResponse(resp);
	}

private:
	AnalyseResult CalculateResult(AnalyseRequest request)
	{
		AnalyseResult res;

		long long elem = ElementAt(request.beginIndex);
		res.maxSum = elem;
		res.maxSumFromBeginning = elem;
		auto total = elem;

		long long currMaxSum = elem;

		for(long long i = request.beginIndex + 1; i <= request.endIndex; ++i)
		{
			long long elem = ElementAt(i);
			total += elem;

			if(elem > currMaxSum + elem) //start new sub table
				currMaxSum = elem;
			else //continue last sum
				currMaxSum = currMaxSum + elem;

			if(currMaxSum > res.maxSum)
			{
				res.maxSum = currMaxSum;
			}

			if(total > res.maxSumFromBeginning)
				res.maxSumFromBeginning = total;
		}

		res.lastRangeSum = currMaxSum;

		return res;
	}

	void SendResponse(AnalyseResult resp)
	{
		PutLL(MergeNodeId, resp.maxSum);
		PutLL(MergeNodeId, resp.maxSumFromBeginning);
		PutLL(MergeNodeId, resp.lastRangeSum);

		Send(MergeNodeId);
	}

	AnalyseRequest ReceiveAnalyseRequest()
	{
		Receive(MergeNodeId);

		AnalyseRequest request;
		request.beginIndex = GetLL(MergeNodeId);
		request.endIndex = GetLL(MergeNodeId);

		return request;
	}
};

int main()
{
	INodeRunner* runner;
	if(MyNodeId() == 0)
		runner = new MergeNodeRunner();
	else 
	 runner = new SearcherNodeRunner();

	runner->Run();

	delete runner;
}