import java.util.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Solution
{
	public static void main(String[] args) throws IOException {
		BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
		String line = "";
		ArrayList<String> lines = new ArrayList<String>();
		ArrayList<Integer> sums = new ArrayList<Integer>();
		while(line!=null) {
			line = reader.readLine();
		}
		int players = Integer.parseInt(lines.get(0));
		for(int i=0; i<players; i++) {
			int sum = 0;
			for(String s: lines.get(i).split(" ")) {
				sum += Integer.parseInt(s);
			}
			sums.add(sum);
		}
		Collections.sort(sums);
		int max = 0;
		int min = 0;
		for(int i=0; i<players/2; i++) {
			max += sums.get(players-i-1);
			min += sums.get(i);
		}
		System.out.println((max-min)/2);
	}
}