#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace __gnu_pbds;
#define DEFAULT 5e5 + 5
#define int long long
#define i64 long long
#define i128 __int128
#define ull unsigned long long
#define db double
#define ldb long double
#define Arr std::vector
#define Ptn std::pair
#define fi first
#define se second
#define eb emplace_back
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define popc(x) __builtin_popcountll(x)
#define clz(x) __builtin_clzll(x)
#define ctz(x) __builtin_ctzll(x)
#define chkmin(x, y) x = std::min(x, y)
#define chkmax(x, y) x = std::max(x, y)
#define FILE(x) freopen(x ".in", "r", stdin), freopen(x ".out", "w", stdout)
#define TEST(x) freopen(x ".in", "r", stdin), freopen("test.out", "w", stdout)
#define KEL(x) freopen(x ".in", "r", stdin), freopen("a.out", "w", stdout)
#define debug std::cout << "Running on " << __FUNCTION__ << ' ' << __LINE__ << std::endl;
#define fail assert(0);
#define lopzith return 0;
bool BeginPoint;
const int INF = 0x3f3f3f3f, llINF = 0x3f3f3f3f3f3f3f3f, P = 998244353;
const db eps = 1e-9;
const ull base = 13331;
const int N = 1e5 + 5;
int _, n, a[N], b[N], fa[N], _fa[N], vis[N];
Arr<int> e[N];
struct LOP
{
    int a, b, id;
    friend bool operator < (LOP x, LOP y)
    {
        return std::max(x.a, x.a + y.a - x.b) > std::max(y.a, x.a + y.a - y.b);
    }
};
std::priority_queue<LOP> S;
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 << 3) + (w << 1) + (ch - 48);
        ch = getchar();
    }
    return w * f;
}

void DFS(int p)
{
    for (auto to : e[p])
    {
        if (to == fa[p]) continue;
        fa[to] = p;
        DFS(to);
    }
}

int find(int x) { return _fa[x] == x ? x : _fa[x] = find(_fa[x]); }

void Solve()
{
    vis[1] = 1;
    while (!S.empty())
    {
        auto x = S.top(); S.pop();
        if (vis[x.id] || x.a != a[x.id] || x.b != b[x.id]) continue;
        vis[x.id] = 1;
        int Fa = find(fa[x.id]);
        int A = std::max(a[Fa], a[Fa] - b[Fa] + a[x.id]), B = A + b[Fa] + b[x.id] - a[Fa] - a[x.id];
        a[Fa] = A, b[Fa] = B;
        _fa[x.id] = Fa;
        S.push((LOP){a[Fa], b[Fa], Fa});
    }
    printf("%lld\n", a[1]);
    for (int i = 1; i <= n; i++) a[i] = b[i] = 0;
}

bool EndPoint;
signed main()
{
    std::cerr << "Memory = " << fabs(&BeginPoint - &EndPoint) / 1048576.0 << "MB" << std::endl;

    _ = read();
    while (_--)
    {
        n = read(); 
        while (!S.empty()) S.pop();
        for (int i = 2; i <= n; i++)
        {
            int A = read(), B = read();
            a[i] = A, b[i] = B;
            S.push((LOP){A, B, i});
        }
        for (int i = 0; i <= n; i++)
        {
            _fa[i] = i, fa[i] = vis[i] = 0;
            e[i].clear();
        } // clear
        for (int i = 1; i < n; i++)
        {
            int u = read(), v = read();
            e[u].eb(v), e[v].eb(u);
        }
        DFS(1);
        Solve();
    }

    std::cerr << "Time = " << (double)clock() / CLOCKS_PER_SEC << "s" << std::endl;
    lopzith
}