#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n, k;
    if (!(cin >> n >> k)) return 0;

    vector<int> a(n + 1);
    for (int i = 1; i <= n; ++i) cin >> a[i];

    vector<vector<int>> g(n + 1);
    for (int i = 0; i < n - 1; ++i) {
        int u, y; 
        cin >> u >> y;
        g[u].push_back(y);
        g[y].push_back(u);
    }

    int s = 0;
    int t = k + n + 1;
    int m = t;

    vector<vector<int>> h(m + 1);
    vector<int> v, c, f; 

    auto d = [&](int u, int y, int z) { 
        h[u].push_back(v.size());
        v.push_back(y); c.push_back(z); f.push_back(0);

        h[y].push_back(v.size());
        v.push_back(u); c.push_back(0); f.push_back(0);
    };

    for (int j = 1; j <= n; ++j) {
        d(k + j, t, a[j]);
    }

    for (int i = 1; i <= k; ++i) {
        int u, y, z; 
        cin >> u >> y >> z;
        
        d(s, i, z);

        vector<int> tr(n + 1, 0);
        queue<int> q;
        q.push(u);
        tr[u] = -1;
        while (!q.empty()) {
            int cur = q.front(); q.pop();
            if (cur == y) break;
            for (int nxt : g[cur]) {
                if (tr[nxt] == 0) {
                    tr[nxt] = cur;
                    q.push(nxt);
                }
            }
        }

        int x = y;
        while (x != -1) {
            d(i, k + x, 1e9);
            x = tr[x];
        }
    }

    long long kq = 0; 
    vector<int> p(m + 1);

    while (true) {
        fill(p.begin(), p.end(), -1);
        queue<int> q;
        q.push(s);

        while (!q.empty()) {
            int u = q.front(); q.pop();
            for (int id : h[u]) {
                int y = v[id]; 
                if (p[y] == -1 && y != s && c[id] - f[id] > 0) {
                    p[y] = id;
                    q.push(y);
                }
            }
        }

        if (p[t] == -1) break;

        int w = 1e9; 
        int x = t;   
        while (x != s) {
            int id = p[x];
            w = min(w, c[id] - f[id]);
            x = v[id ^ 1]; 
        }

        x = t; 
        while (x != s) {
            int id = p[x];
            f[id] += w;
            f[id ^ 1] -= w; 
            x = v[id ^ 1];
        }
        kq += w; 
    }

    cout << kq << "\n";
    return 0;
}
#Haolac