#include <stdio.h>

int one, two, three, four;

int max(int a, int b){
	return a>=b?a:b;
}

void checkQuadrant(int x, int y){
	if(x>0 && y>0){
		one++;
	}else if(x<0 && y>0){
		two++;
	}else if(x<0 && y<0){
		three++;
	}else if(x>0 && y<0){
		four++;
	}
}

int main(){
	int tc, x, y, n;
	scanf("%d", &tc);
	for(int i=1;i<=tc;i++){
		one=two=three=four=0;
		scanf("%d", &n);
		for(int j=0;j<n;j++){
			scanf("%d %d", &x, &y);
			checkQuadrant(x, y);
		}
		printf("Case #%d: %s\n", i, n-max(one,max(two,max(three,four)))>1?"NO":"YES");
	}
	return 0;
}