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

public class Main {

    public static void main(String[] args) throws IOException {
        BufferedReader scanner = new BufferedReader(new InputStreamReader(System.in));

        int n = Integer.parseInt(scanner.readLine());
        int[] x = new int[n];
        int[] y = new int[n];
        int i = 0;
        while (n-- != 0) {
            String[] line = scanner.readLine().split(" ");
            x[i] = Integer.parseInt(line[0]);
            y[i] = Integer.parseInt(line[1]);
            i++;
        }
        int count = 0;
        int sample = x[0];
        for (int j = 1; j < x.length; j++)
        {
            if(sample != x[j])
            {
                count = 1;
                break;
            }
        }
        if(count != 0)
        {
            sample = y[0];
            for (int j = 1; j < y.length; j++)
            {
                if(sample != y[j])
                {
                    count = 2;
                    break;
                }
            }
        }
        if(count != 2)
            System.out.println("YES");
        else
            System.out.println("NO");
    }
}