#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5;
int n,r[N],s[N];
vector<int> add[N],del[N];
inline void Main() {
	cin >> n;
	for(int i = 1;i <= n;i++) cin >> r[i] >> s[i];
	for(int i = 1;i <= n;i++) add[i].clear(),del[i].clear();
	for(int i = 1;i <= n;i++) {
		int l = max(1,i - r[i]),tr = min(n,i + r[i]);
		add[l].push_back(s[i]);del[tr + 1].push_back(s[i]);
	}
	int ans = 0;
	multiset<int> S;
	for(int i = 1;i <= n;i++) {
		for(auto j : add[i]) S.insert(j);
		for(auto j : del[i]) S.erase(S.find(j));
		if(S.size() >= 3) {
			auto i1 = --S.end(),i2 = prev(i1),i3 = prev(i2);
		ans = max(ans,*i1 + *i2 + *i3);
		}
	}
	cout << ans << endl;
}
int main() {
	int T;
	cin >> T;
	while(T--) Main();
	return 0;
}