#include<bits/stdc++.h>
#define int long long
#define fi first
#define se second
#define MULT_TEST 1
using namespace std;
typedef long double ldb;
typedef unsigned long long ull;
const int INF = 0x3f3f3f3f;
const int MOD = 998244353;
const int N = 100005;
int f[N], x[N], y[N];
bool vis[N];
vector<int> e[N];
struct node {
    int a, b, id;
    bool operator < (const node &T) const {
        return max(a, a + T.a - b) > max(T.a, a + T.a - T.b);
    }
};
struct dsu {
    vector<int> fa;
    dsu(int n) : fa(n + 2) { iota(fa.begin(), fa.end(), 0); };
    inline int Find(int r) {
        while (r != fa[r]) r = fa[r] = fa[fa[r]];
        return r;
    }
    inline bool Merge(int x, int y) {
        x = Find(x); y = Find(y);
        if (x == y) return true;
        else return fa[y] = x, false;
    }
};
inline int read() {
    int w = 0, f = 1;
    char ch = getchar();
    while (ch < '0' || ch > '9') {
        if (ch == '-') f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9') {
        w = (w << 1) + (w << 3) + ch - 48;
        ch = getchar();
    }
    return w * f;
}
inline void DFS(int x) {
    for (auto u : e[x]) {
        if (u == f[x]) continue;
        f[u] = x, DFS(u);
    }
}
inline void Solve() {
    int n;
    n = read();
    priority_queue<node> q;
    q.push((node){0, 0, 1});
    for (int i = 2; i <= n; i++) {
        x[i] = read(), y[i] = read();
        q.push((node){x[i], y[i], i});
    }
    for (int i = 1; i < n; i++) {
        int u = read(), v = read();
        e[u].push_back(v), e[v].push_back(u);
    }
    DFS(1);
    dsu A(n);
    while (!q.empty()) {
        auto [a, b, id] = q.top(); q.pop();
        if (vis[id]) continue;
        vis[id] = 1;
        if (id == 1) continue;
        int top = A.Find(f[id]);
        x[top] = max(x[top], x[top] - y[top] + x[id]);
        y[top] = max(y[top], y[top] - x[id] + y[id]);
        q.push((node){x[top], y[top], top});
        A.Merge(top, id);
    }
    printf("%lld\n", x[1]);
    for (int i = 1; i <= n; i++) e[i].clear(), vis[i] = 0;
}
signed main() {
    int _ = 1;
#if MULT_TEST
    _ = read();
#endif 
    while (_--) Solve();
    return 0;
}