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_storage = [];
    var y_storage = [];
    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 (x_storage.length === 0) {
            x_storage.push(x)
        }
        if (y_storage.length === 0) {
            y_storage.push(y)
        }
        else if (x_storage[0] === x) {
            x_storage.push(x)
        }
        else if (y_storage[0] === y) {
            y_storage.push(y)
        }
        
    }
    if (x_storage.length === n || y_storage.length === n) {
        console.log('YES')
    } else {
        console.log('NO')
    }

}