#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>

const int mxn = 100005;

// Comparator struct for comparing two pii pairs
struct Comp {
    bool operator()(const pii& a, const pii& b) const {
        return max(a.first, -a.second + a.first + b.first) < max(b.first, -b.second + b.first + a.first);
    }
};

// Comparator for the priority_queue that contains a pair of pii and int
struct Cmp {
    bool operator()(const pair<pii, int>& a, const pair<pii, int>& b) const {
        Comp comp;
        return comp(a.first, b.first);
    }
};

signed main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int t;
    cin >> t;
    while (t--) {
        int n;
        cin >> n;
        vector<vector<int>> adj(n+1);
        vector<bool> vis(n+1);
        priority_queue<pair<pii, int>, vector<pair<pii, int>>, Cmp> pq;
        vector<int>a(n+1);
        vector<int>b(n+1);
        for(int i = 2; i<=n; i++){
        	cin >> a[i] >> b[i];
        }
        for(int i = 2; i<=n; i++){
        	int x,y;
        	cin >> x >> y;
        	adj[x].push_back(y);
        	adj[y].push_back(x);
        }
        vis[1] = true;
        pq.push({{a[1],b[1]},1});
        int rq = 0;
        int ans = 0;
        while(pq.size()){
        	auto [p,i] = pq.top();
        	pq.pop();
        	rq+=p.first;
        	ans = max(ans,rq);
        	rq-=p.second;
        	for(int nxt: adj[i]){
        		if(vis[nxt])continue;
        		vis[nxt] = true;
        		pq.push({{a[nxt],b[nxt]},nxt});
        	}
        }
        cout << ans << '\n';
    }
    return 0;
}