process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var n = parseInt(readLine());
    var xs = [];
    var ys = [];
    for(var a0 = 0; a0 < n; a0++){
        var x_temp = readLine().split(' ');
        var x = parseInt(x_temp[0]);
        var y = parseInt(x_temp[1]);
        if (xs.indexOf(x) === -1) xs.push(x);
        if (ys.indexOf(y) === -1) ys.push(y);
    }
    if (xs.length === 1 || ys.length === 1 ) console.log('YES');
    else console.log('NO');

}