import java.util.*;

public class Main {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

int t = sc.nextInt();

for(int i = 0;i< t;i++) {

int q = 0;

int z = 0;

int m = sc.nextInt();

if(m==0) {

System.out.println(3);

continue;

}

Map<String,Integer> r1 =new HashMap<>();

Map<String,Integer> r2 =new HashMap<>();

for(int j = 0; j < m;j++) {

int y = sc.nextInt();

int x = sc.nextInt();

if(((x==-1&&y==1)||(x==1&&y==1))) {

q = 1;

z++;

}

if(x>0) r1.put(x+" "+y, 1);

else if(x<0) r2.put(x+" "+y, 1);

else {

r1.put(x+" "+y, 1);

r2.put(x+" "+y, 1);

}

}

System.out.println(Math.min(cnt(r1)+cnt(r2), 3-z));

}

}

public static int cnt(Map<String,Integer> map) {

if(map.isEmpty()) return 2;

for(String s:map.keySet()) {

String[] arr = s.split(" ");

int x = Integer.parseInt(arr[0]);

int y = Integer.parseInt(arr[1]);

if(y==1) {

if(map.get((x-1)+" "+2)!=null||map.get((x+1)+" "+2)!=null||map.get(x+" "+2)!=null) return 0;

}else {

if(map.get((x-1)+" "+1)!=null||map.get((x+1)+" "+1)!=null||map.get(x+" "+1)!=null) return 0;

}

}

return 1;

}

}