#include <bits/stdc++.h>
using namespace std;


int main() {
    int q, n;
    scanf("%i", &q);
    while(q--)
    {
        int take;
        bool ok = false;
        scanf("%i", &n);
        for(int i = 0;i < n; i++){
            int x, y;
            scanf("%i %i", &x, &y);
            take = max(take, max(x, y));
            if(x == 0 or y == 0)ok = false;
            if(x > 0  and y > 0){
                if(x == take or y == take)ok = false;
                if(x < take and y < take)ok = true;
            }
        }
        if(ok == false) puts("YES");
        else puts("NO");
    }



    return 0;
}