#!/usr/bin/perl
use Data::Dumper;
$n = <>;
chomp $n;
@coord = ();
for $i (0..$n-1) {
    $coord[$i] = [ split " ",<> ];
}
#print Dumper(@coord); 
$x = $coord[0][0];
$y = $coord[0][1];
$ch1 = 0;
$ch2 = 0;
for $i (1..$n-1) {
    $ch1 = 1 if (!($x == $coord[$i][0]));
    $ch2 = 1 if (!($y == $coord[$i][1]));
}

if  ($ch1 == 1 && $ch2 == 1) {
    print "NO\n";
}
else {
    print "YES\n";
}