'use strict';

function processData(input) {
    let lines = input.split("\n");
    let nrQueries = parseInt(lines[0]);
    
    //console.error("queries " + nrQueries);
    let nrLine = 1;
    for (let i=0; i<nrQueries; i++) {
        let nrDots = parseInt(lines[nrLine++]) || 0;
        let minX = 10000;
        let maxX = -10000;
        let minY = 10000;
        let maxY = -10000;
        let dots = [];
        for (let j = 0; j < nrDots; j++) {
            let dotStr = lines[nrLine++].split(" ");
            let x = parseInt(dotStr[0]);
            let y = parseInt(dotStr[1]);
            dots.push([x, y]);
            
            if (maxX < x) {
                maxX = x;
            }
            if (minX > x) {
                minX = x;
            }
            if (maxY < y) {
                maxY = y;
            }
            if (minY > y) {
                minY = y;
            }
        }
        let good = true;
        //console.error(maxX + " / " +maxX + " / " + minY + " / " + maxY)
        for (let j = 0; j < dots.length; j++) {
            if (dots[j][0] != minX
               && dots[j][0] != maxX
               && dots[j][1] != maxY
               && dots[j][1] != minY ) {
               good = false;
               break;
            }
        }
        if (good) {
            console.log("YES");
        } else {
            console.log("NO");
        }
    }
    //Enter your code here
} 

process.stdin.resume();
process.stdin.setEncoding("ascii");
let _input = "";
process.stdin.on("data", function (input) {
    _input += input;
});

process.stdin.on("end", function () {
   processData(_input);
});