#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int, int> pii;
#define M(x) {x%=mod;if(x<0) x+=mod;}
#define error           \
    {                   \
        cout << "No\n"; \
        return;         \
    }
#define all(x) (x.begin(), x.end())
const int N = 1e6 + 10;
int a[N];
int n, m;
int l[N],r[N];
bool tui[N];
void solve()
{
    int n;
    cin>>n;
    for(int i=1;i<=n;i++){

        cin>>l[i]>>r[i];
        tui[i]=0;
    }
    int ans=0;
    int msk=0;
    for(int i=29;i>=0;i--){

        msk += 1 << i;
        int f=1;
        for(int j=1;j<=n;j++){

            if(f==0) break;
            if (!((r[j] & (1 << i)) || tui[j] && ((r[j] & msk) - 1 >= l[j])))
                f = 0;
        }
        
        if(f==1){

            ans+=1<<i;
            for(int j=1;j<=n;j++){

                if ((r[j] & (1 << i))) continue;
                if(tui[j]) r[j] = (r[j] & msk)-1;
            }
        }
        
        for(int j=1;j<=n;j++){

            if((msk&r[j])!=ans) tui[j]=1;
        }
    }
    cout<<ans<<"\n";
}
signed main()
{

    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t;
    cin >> t;
    while (t--)
    {

        solve();
    }
}