#include <bits/stdc++.h>
using namespace std;
#define clo 1000.*clock()/CLOCKS_PER_SEC
#ifndef xxzx
#define endl '\n'
#endif
using ll=long long;
using PII=pair<int,int>;
const int N=1e5+10;
bool memory1;
int n;
ll a[N],b[N];
vector<int> eg[N];
struct cmp {
    bool operator()(const int &x,const int &y) {
        if((a[x]<=b[x])!=(a[y]<=b[y])) return (a[x]>b[x]);
        if(a[x]<=b[x]) return a[x]>a[y];
        return b[x]<b[y];
    }
};
int fa[N];
void dfs(int x) {
    for(auto y:eg[x]) if(y!=fa[x]) fa[y]=x,dfs(y);
}
int f[N];
int find(int x) { return (x==f[x])? x:f[x]=find(f[x]); }
void solve() {
    cin>>n;
    priority_queue<int,vector<int>,cmp> q;
    for(int i=1;i<=n;i++) eg[i].clear(),f[i]=i;
    for(int i=2;i<=n;i++) cin>>a[i]>>b[i],q.push(i);
    for(int i=1,x,y;i<n;i++) cin>>x>>y,eg[x].push_back(y),eg[y].push_back(x);
    dfs(1);
    ll v1=0,v2=0;
    while(q.size()) {
        int x=q.top(); q.pop();
        int y=find(fa[x]);
        if(y!=1) {
            ll w=-a[x]+b[x]-a[y]+b[y];
            a[y]=max(a[y],a[x]-(-a[y]+b[y]));
            b[y]=w+a[y];
        }
        else {
            v2=max(v2,a[x]-v1);
            v1=v1-a[x]+b[x];
        }
        f[x]=y;
    }
    cout<<v2<<endl;
}
bool memory2;
int main() {
    ios::sync_with_stdio(false), cin.tie(nullptr);

    int T; cin>>T;
    while(T--) solve();

    #ifdef xxzx
    cerr<<"Time: "<<clo<<"MS"<<endl;
    cerr<<"Memory: "<<abs(&memory1-&memory2)/1024./1024.<<"MB"<<endl;
    #endif
    return 0;
}