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 x_intact = true;
    var y_intact = true;
    var prev_x;
    var prev_y;
    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 (a0 === 0) {
            prev_x = x;
            prev_y = y;
        }
        if (x !== prev_x) {
            x_intact = false;
        }
        if (y !== prev_y) {
            y_intact = false;
        }
        if (x_intact === false && y_intact === false) {
            console.log("NO");
            return;
        }
    }
    console.log("YES");
}