#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
#define FILL(a, b) memset(a, b, sizeof(a))

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;


bool check(int l, int r, int val, int lbit, int rbit){
	//exist x: x in [l, r] and val <= x % (2 ^ rbit) < val + (2 ^ lbit);
	int mod = 1 << rbit;
		
	int L = max(0, (l / mod) - 1);
	L *= mod;
	L += val;
	int R = L + (1 << lbit) - 1;
	
	while(L <= r){
		if(max(l, L) <= min(r, R))
			return 1;
		
		L += mod;
		R += mod;
	}
	return 0;
}

void solve(){
	int n;
	cin >> n;
	vector<PII> a(n);
	FOR(i, 0, n)
		cin >> a[i].F >> a[i].S;
	
	int rbit = 30;
	while(rbit > 0){
		bool ok = 1;
		FOR(i, 0, n){
			//from l to r we have rbit
			ok &= check(a[i].F, a[i].S, 1 << rbit, rbit, rbit + 1);
		}
		if(ok)
			break;
		rbit--;
	}
	rbit++;
	
	int val = 0;
	RFOR(bit, rbit, 0){
		bool ok = 1;
		FOR(i, 0, n)
			ok &= check(a[i].F, a[i].S, val + (1 << bit), bit, rbit);
		if(ok)
			val += 1 << bit;
	}
	cout << val << "\n";
}


int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while(t--)
		solve();
	
	
	return 0;
}