#include<stdio.h>
#include<iostream>
#include<algorithm>
#define inf 0X7fffffff
using namespace std;
const int N=2e6+9;
int read(int &x){
    int dat=0,oko=1;char chc=getchar();
    while(chc<'0'||chc>'9'){if(chc=='-')oko=-1;chc=getchar();}
    while(chc>='0'&&chc<='9'){dat=dat*10+chc-'0';chc=getchar();}
    x=dat*oko;return x;
}int T,n,a,b,flag;bool vis[N];
int cnt,head[N],nxt[N<<1],to[N<<1];
void link(int f,int t){
    nxt[++cnt]=head[f],head[f]=cnt,to[cnt]=t;
}void dfs(int x){
    vis[x]=true;
    for(int i=head[x];i;i=nxt[i]){
        if(vis[to[i]]){
            flag=0;return;
        }dfs(to[i]);
    }
}int main(){
    read(T);
    while(T--){
        read(n);cnt=0;flag=1;
        for(int i=1;i<=n+1;i++){
            head[i]=0;vis[i]=false;
        }for(int i=1;i<=n;i++){
            read(a),read(b);
            link(a,b+1);
        }dfs(1);printf("%d\n",flag);
    }return 0;
}