#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
float area(int x1,int y1,int x2,int y2,int x3,int y3);
int main() {

    int t,i,j,n,x[10],y[10];
    scanf("%d",&t);
    for(i=0;i<t;i++)
        {
        scanf("%d",&n);
        for(j=0;j<n;j++)
            {
            scanf("%d %d",&x[j],&y[j]);
            }
        if(n<=3)
            printf("YES\n");
        else if(n==4)
            {
            if(area(x[0],y[0],x[1],y[1],x[2],y[2])==area(x[0],y[0],x[1],y[1],x[3],y[3])+area(x[0],y[0],x[2],y[2],x[3],y[3])+area(x[1],y[1],x[2],y[2],x[3],y[3]))
                printf("NO\n");
            else
                printf("YES\n");
        }
    }
    return 0;
}
float area(int x1,int y1,int x2,int y2,int x3,int y3)
    {
    float a;
    a=x1*(y2-y3)+x2*(y3-y1)+x3*(y1-y2);
    if(a<0)
        a=-a;
    return a/2;
    
}