#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const int N=1e5+5;
int T;
int n;
ll a[N],b[N];
vector<int> e[N];
int fa[N];
void dfs(int no,int ff){
    fa[no]=ff;
    for(int to:e[no]){
        if(to==ff)continue;
        dfs(to,no);
    }
}
struct node{
    int id;
    ll a,b;
    bool fl;
    node()=default;
    node(int id,ll a,ll b):id(id),a(a),b(b),fl(b>=0){}
    bool operator<(const node& y)const{
        if(fl!=y.fl)return fl<y.fl;
        if(fl)return a>y.a;
        return b<y.b;
    }
};
priority_queue<node> q;
int f[N];
bool fl[N];
int find(int x){return f[x]==x?x:f[x]=find(f[x]);}
int main(){
    scanf("%d",&T);
    while(T--){
        scanf("%d",&n);
        for(int i=1;i<=n;++i){
            a[i]=b[i]=0;
            e[i].clear();
            fa[i]=0;
            fl[i]=0;
        }
        for(int i=2;i<=n;++i)scanf("%lld%lld",&a[i],&b[i]);
        for(int i=1;i<n;++i){
            int u,v;
            scanf("%d%d",&u,&v);
            e[u].push_back(v);
            e[v].push_back(u);
        }
        for(int i=1;i<=n;++i)f[i]=i;
        dfs(1,0);
        for(int i=2;i<=n;++i){
            b[i]-=a[i];
            q.emplace(i,a[i],b[i]);
        }
        while(!q.empty()){
            int no=q.top().id;
            ll lsa=q.top().a,lsb=q.top().b;
            q.pop();
            if(lsa!=a[no]||lsb!=b[no])continue;
            if(fl[no])continue;
            fl[no]=1;
            int fid=find(fa[no]);
            a[fid]=max(a[fid],a[no]-b[fid]);
            b[fid]+=b[no];
            f[no]=fid;
            if(fid!=1)q.emplace(fid,a[fid],b[fid]);
        }
        printf("%lld\n",a[1]);
    }
    return 0;
}