#include <iostream>
#include <string>

int main(int argc, char* argv[])
{
    std::string line;
    int total = 0;
    int max = 0;
    while(std::getline(std::cin, line))
    {
        if (0 == line.size())
        {
            if (total > max)
            {
                max = total;
            }
            total = 0;   
        }
        else
        {
            total += stoi(line);
        }
    }
    std::cout << max << std::endl;
}