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

#define all(x) begin(x), end(x)
#ifdef CKISEKI
#define safe cerr << __PRETTY_FUNCTION__ << " line " << __LINE__ << " safe\n"
#define debug(a...) debug_(#a, a)
#define orange(a...) orange_(#a, a)
template <typename ...T>
void debug_(const char *s, T ...a) {
    cerr << "\e[1;32m(" << s << ") = (";
    int cnt = sizeof...(T);
    (..., (cerr << a << (--cnt ? ", " : ")\e[0m\n")));
}
template <typename I>
void orange_(const char *s, I L, I R) {
    cerr << "\e[1;32m[ " << s << " ] = [";
    while (L != R) cerr << " " << *L++;
    cerr << " ]\e[0m\n";
}
#else
#define safe ((void)0)
#define debug(...) safe
#define orange(...) safe
#endif

namespace {

int lowbit(int x) { return x & (-x); }

constexpr int kN = 100000 + 5;
constexpr int kLog = 20;

vector<int> g[kN];
int tin[kN], tout[kN], tc;
int pa[kN][kLog];
int chain[kN], chains;
int head[kN];
void dfs(int u, int f) {
    pa[u][0] = f;
    for (int i = 1; i < kN; ++i)
        pa[u][i] = pa[pa[u][i - 1]][i - 1];
    tin[u] = tc++;
    for (int v : g[u]) {
        if (v == f)
            continue;
        dfs(v, u);
        if (lowbit(chain[u]) < lowbit(chain[v]))
            chain[u] = chain[v];
    }
    if (chain[u] == 0)
        chain[u] = ++chains;
    tout[u] = tc;
    head[chain[u]] = u;
}

bool anc(int u, int v) {
    return tin[u] <= tin[v] and tout[v] <= tout[u];
}

int lca(int u, int v) {
    if (anc(u, v)) return v;
    for (int i = kLog - 1; i >= 0; --i) {
        if (not anc(pa[u][i], v))
            u = pa[u][i];
    }
    return pa[u][0];
}

vector<tuple<int, int, int>> path[kN];

int64_t dp[kN][13];

void solve(int u) {
    for (int v : g[u]) {
        solve(v);
    }
    if (g[u].empty())
        return;

}

} // namespace

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int n, m, k;
    cin >> n >> m >> k;
    for (int i = 1; i < n; ++i) {
        int u, v;
        cin >> u >> v;
        u -= 1, v -= 1;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    dfs(0, 0);
    for (int i = 0; i < m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        u -= 1, v -= 1;
        path[lca(u, v)].emplace_back(u, v, w);
    }

    for (int i = 0; i < n; ++i) {
        int fi = -1;
        vector<int> cur;
        for (int j : g[i]) {
            if (j != pa[i][0]) {
                if (chain[j] == chain[i])
                    fi = j;
                else
                    cur.push_back(j);
            }
        }
        if (fi != -1) {
            cur.push_back(fi);
            reverse(cur.begin(), cur.end());
        }
        g[i] = cur;
    }
    solve(0);
    int64_t ans = 0;
    for (auto r : dp[0])
        ans = max(ans, r);
    cout << ans << '\n';
    return 0;
}