#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define max(A,B) (A>B? A:B)
#define min(A,B) (A<B? A:B)
#define mpr(A,B) make_pair(A,B)
using namespace std;

template <class T> void read(T &x){
	x=0;
	char c=getchar(),d='0';
	while(c<'0'||c>'9') d=c,c=getchar();
	while(c>='0'&&c<='9') x=(x<<3)+(x<<1)+c-'0',c=getchar();
	if(d=='-') x=-x;
}
template <class T> void wt(T x){
	if(x/10) wt(x/10);
	putchar(x%10+'0');
}
template <class T> void enter(T x){
	if(x<0) x=-x,putchar('-');
	wt(x),putchar('\n');
}
template <class T> void space(T x){
	if(x<0) x=-x,putchar('-');
	wt(x),putchar(' ');
}

const int N=1e6+10;

int l[N],r[N];
vector<int> t[N];
bool flg[N];

void dfs(int pos){
	flg[pos]=1;
	for(int v:t[pos]) if(!flg[v]){
		dfs(v);
	}
}

void slv(){
	set<int> st;
	set<pair<int,int>> e;
	int n;
	cin>>n;
	for(int i=1;i<=n;i++) cin>>l[i]>>r[i];
	for(int i=1;i<=n+1;i++) t[i].clear(),flg[i]=0;
	for(int i=1;i<=n;i++){
		t[l[i]].push_back(r[i]+1);
		t[r[i]].push_back(l[i]);
		if(e.count(mpr(l[i],r[i]+1))){
			cout<<0<<'\n';
			return;
		}
		e.insert(mpr(l[i],r[i]+1));
		st.insert(l[i]),st.insert(r[i]+1);
	}
	if(!st.count(1)||st.size()!=e.size()+1){
		cout<<0<<'\n';
		return;
	}
	dfs(1);
	for(int i:st) if(!flg[i]){
		cout<<0<<'\n';
		return;
	}
	cout<<1<<'\n';
	return;
}

int main(){
	int T;
	read(T);
	while(T--) slv();
	return 0;
} 

/*

4
5
1 2
1 5
1 2
1 2
2 2
5
1 1
2 4
2 3
5 5
3 4
5
3 5
1 2
3 4
3 5
3 3
5
1 5
1 4
4 5
5 5
1 2

*/