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 isHorizontal = true;
    var isVertical = true;
    var arrayCoord = [];
    for(var a0 = 0; a0 < n; a0++){
        var x_temp = readLine().split(' ');
        var x = parseInt(x_temp[0]);
        var y = parseInt(x_temp[1]);
        arrayCoord[a0] = [x, y];
    }
    
    for (var a0 = 0; a0 < (n - 1); a0++) {
        if (arrayCoord[a0][0] != arrayCoord[a0 + 1][0]) {
            isVertical = false;
        }
        if (arrayCoord[a0][1] != arrayCoord[a0 + 1][1]) {
            isHorizontal = false;
        }
    }
    
    if (isVertical || isHorizontal) {
        process.stdout.write('YES');
    } else {
        process.stdout.write('NO');
    }
}