function processData(input) {
	var inp = input.split('\n');
	var q = +inp[0];
    
    main_loop:
    for(var i=0, k=1; i<q; i++) {
        var n = +inp[k++];
        var xs = Array(n);
        var ys = Array(n);
        var p = Array(n);
        
        for(var j=0; j<n; j++) {
            var [x,y] = inp[k++].split(' ').map(Number);
            xs[j] = x;
            ys[j] = y;
            p[j] = [x,y];
        }
        
        xs.sort(cmp);
        ys.sort(cmp);
        
        var x1 = xs[0];
        var x2 = xs[n-1];
        var y1 = ys[0];
        var y2 = ys[n-1];
        
        for(var j=0; j<n; j++) {
            var [x,y] = p[j];
            if(!(x==x1 || x==x2 || y==y1 || y==y2)) {
                console.log('NO');
                continue main_loop;                                
            }
        }
        
        
        console.log('YES');
    }
} 

function cmp(a,b) {
    return a-b;
}

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

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