#include <bits/stdc++.h>

using namespace std;

int main()

{

    string input;

    while (cin >> input)

    {

        istringstream iss(input);

        string temp;

        vector<int> vec;

        while (getline(iss, temp, ','))

        {

            vec.push_back(atoi(temp.c_str()));

        }

        sort(vec.begin(), vec.end());

        cout << vec[vec.size() / ] << endl;

    }

    return ;

}