uva1467

#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 505;
int n, p;
struct Node {
    
	int s, d;
	bool operator<(const Node& input) {
    
		return d < input.d;
	}
}node[maxn];

int test(int x)
{
    
	int t = 0, a = 0, b = 0, k = 0;
	for (int i = 0; i <= p; ++i)
	{
    
		if (i == x) continue;
		t += node[i].s;
		k = max(0, t - node[i].d);
		b = max(b, k);
		if (b > a) swap(a, b);
	}
	t += node[x].s;
	k = max(0, t - node[x].d);
	b = max(b, k);
	return a + b;
}
int main()
{
    
	int t;
	cin >> t;
	while (t--) {
    
		cin >> n;
		for (int i = 0; i < n; i++) {
    
			cin >> node[i].s >> node[i].d;
		}
		sort(node, node + n);

		int a = 0, b = 0, t = 0, v;
		for (int i = 0; i < n; i++) {
    
			t += node[i].s;
			v = max(0, t - node[i].d);
			if (v > b) {
    
				b = v;
				p = i;
			}
			if (b > a)swap(a, b);
		}
		int ans = a + b;
		for (int i = 0; i < p; ++i)
			ans = min(ans, test(i));
		cout << ans << endl;
	}
	return 0;
}