#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;

void solve()
{
	int n;
	cin >> n;
	vector<PII> v(n);
	FOR (i, 0, n) cin >> v[i].F >> v[i].S;
	int ans = 0;
	RFOR (j, 30, 0)
	{
		int x = (1 << j) | ans;
		bool ok = 1;
		FOR (i, 0, n) if (v[i].F > x || x > v[i].S) ok = 0;
		if (ok) ans = x;
	}
	cout << ans << '\n';
}

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