#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main(){
    int querry,flag;
    scanf(" %d",&querry);
    for(int i=0;i<querry;i++){
        int enteries;
        scanf(" %d",&enteries);
        for(int j=0;j<enteries;j++){
            int x,y;
            scanf("%d %d",&x,&y);
            if(x==0 || y==0){
                flag++;
            }else{
                flag=0;
            }
        }
        if(flag>0){
            printf("YES\n");
        }else{
            printf("NO");
        }
    }
    
    return 0;
}