// Hydro submission #674721369592d6097b8707e5@1732714807284
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define x first
#define y second
typedef pair<int, int> PP;
typedef double db;
const int N = 1e5 + 5;
const int mod = 1e9 + 7;
const int inf = 0x3f3f3f3f;
vector<int> v[N];
int fa[N], n, a[N], b[N], pos[N], fa1[N];
int check(int i) {
    if(a[i] <= b[i]) return 1;
    return 2;
}
struct node {
    int x;
    bool operator < (const node k) const{    
        int wasd = k.x, dsaw = x;
        if(check(wasd) != check(dsaw)) return check(wasd) < check(dsaw);
        else {
            if(check(wasd) & 1) return a[wasd] < a[dsaw];
            else return b[wasd] > b[dsaw];
        }
    }
};
void findfa(int x, int ffa) {
    fa1[x] = ffa;
    for(int wasd : v[x]) {
        if(wasd == ffa) continue;
        findfa(wasd, x);
    }
}
int find(int x) {
    if(fa[x] == x) return x;
    return fa[x] = find(fa[x]);
}

priority_queue<node> q;
void merge(int x, int y) {
    int now = 0, mi = 0;
    now -= a[x], mi = min(mi, now);
    now += b[x], mi = min(mi, now);
    now -= a[y], mi = min(mi, now);
    now += b[y], mi = min(mi, now);
    // cout << now << endl;
    a[x] = -mi;
    b[x] = now - mi;
    fa[find(y)] = find(x);
}
signed main() {
    // freopen("tree.in", "r", stdin);
    // freopen("tree.out", "w", stdout);
    // freopen("tree.out", "w", stdout);
    int T; cin >> T; while(T --) {
        cin >> n;
        int ans = 0;
        a[1] = b[1] = 0;
        for(int i = 2; i <= n; i ++) {
            scanf("%lld%lld", &a[i], &b[i]);
        }
        for(int i = 1; i < n; i ++) {
            int wasd, dsaw; scanf("%lld%lld", &wasd, &dsaw);
            v[wasd].push_back(dsaw), v[dsaw].push_back(wasd);
            fa[i] = i;
        }
        fa[n] = n, findfa(1, 0);
        for(int i = 2; i <= n; i ++) q.push({i});
        while(!q.empty()) {
            int i = q.top().x; q.pop();
            int f = find(fa1[i]);
            merge(f, i);
            // cout << f << ' ' << a[1] << ' ' << b[1] << endl;
        }
        cout << a[1] << endl;
        for(int i = 1; i <= n; i ++) v[i].clear();
    }
    return 0;
}