#include <stdio.h>
#include <iostream.h>
#include <fstream.h>

//采用和書上一樣的算法      -_-!~~~~
int MaxSum(int n,int *a)
{ 
	int sum=0,b=0;
    for (int i=1;i<=n;i++) {
		if (b>0) b+=a[i];
		else b=a[i];
	    if (b>sum) sum=b;
	}
	return sum;
}


void main()
{ 
	int *a;
	int n;
	int flag=0; //如果有正數，置flag=1. 如遍歷一遍后flag==0，則全負數輸出0，程序結束

	ifstream inFile("input.txt");
    ofstream outFile("output.txt");

	inFile>>n;
	a=new int[n];

	for (int i=1;i<=n;i++) {
		inFile>>a[i];
		if(a[i]>0) flag=1;
	}

	//如果都是負數，輸出0
	if (flag==0) {
		outFile<<0<<endl;
		inFile.close();
		outFile.close();
		return;
	}

	//輸出MaxSum的結果
	outFile<<MaxSum(n,a)<<endl;
	inFile.close();
	outFile.close();

}