#include <algorithm>
#include <iostream>
#include <string>
using namespace std;

class Solution {
	long best = -1;
	long curtotal = 0;
public:

	void addItem(long cals) {
		curtotal += cals;
	}
	void endElf() {
		best = max(best, curtotal);
		curtotal = 0;
	}
	long getAnswer() { return best; }
};


int
main()
{
	Solution sol;
	for (string line; getline(cin, line); ) {
		if (line.length() > 0) {
			sol.addItem(stol(line));
		} else {
			sol.endElf();
		}
	}
	sol.endElf();
	cout << sol.getAnswer() << endl;
}