#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int maxm = 2e5+7;
ll L[maxm],R[maxm],now[maxm];
void solve(){
    ll n;cin>>n;
    for(int i=1;i<=n;i++) cin>>L[i]>>R[i],now[i] = 0;
    ll ans = 0;
    for(ll i = 31;i>=0;i--){
        int flag = 1;
        for(int cur = 1;cur<=n;cur++){
            ll cL = now[cur] + (1ll<<i),cR = now[cur] + (1ll<<(i+1)) - 1;
            if(cL > R[cur] or cR < L[cur]){
                //区间不交
                flag = 0;
                break;
            }
        }
        if(flag){
            ans += (1ll<<i);
            for(int j=1;j<=n;j++) now[j] += (1ll<<i);
        }
        else{
            //当这一位无法填1的时候,分为两种情况
            //1. 只能填0
            //2. 这一位可以填0也可以填1，出现这种情况后说明，只要这一位选0后面就可以随便选
            for(int j=1;j<=n;j++){
                ll cL = now[j] + (1ll<<i),cR = now[j] + (1ll<<(i+1)) - 1;
                if(cL <= R[j] and cR >= L[j]){
                    if(cL - 1 < L[j]) now[j] += (1ll<<i);
                }
            }
        }
    }
    cout<<ans<<'\n';
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);cout.tie(0);
    int T;cin>>T;
    while(T--) solve();
    return 0;
}