#include <bits/stdc++.h>
using namespace std;
#define int              long long int
#define double           long double
#define print(a)         for(auto x : a) cout << x << " "; cout << endl
inline int power(int a, int b) {
    int x = 1;
    while (b) {
        if (b & 1) x *= a;
        a *= a;
        b >>= 1;
    }
    return x;
}


const int M = 1000000007;
const int N = 3e5+9;
const int INF = 2e9+1;
const int LINF = 2000000000000000001;

//_ ***************************** START Below *******************************

vector<int> a;
vector<int> b;

bool isPossible(int n, int mid){
	
	int ct = 0;
	int rem = mid;
	
	for(int i=0; i<n; i++){
		if(a[i] >= rem-1 && b[i] >= ct){
			rem--;
			ct++;
		}	
	}
	
	return ct >= mid;
	
}

int consistency(int n){
	
	int s = 0, e = INF;
	
	while(s<e){
		int mid = s + (e-s+1)/2;
		if(isPossible(n, mid)){
            s = mid;
		}
		else e = mid-1;
	}
	
	return e;

}











void solve() {
    
    int n;
    cin>>n;
    
    a.resize(n);
    b.resize(n);
    for(int i=0; i<n; i++){
        cin >> a[i] >> b[i];
    }
    
    cout << consistency(n) << endl;


}





int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    int t = 1;
    cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}