#include <bits/stdc++.h>

using namespace std;

#define int long long
#define ll long long
#define forn(i, n) for (ll i = 0; i < n; ++i)
#define forr(i, s, n) for (ll i = s; i < n; ++i)
#define fori(i, s, n) for (ll i = s; i > n; --i)
#define fora(i, n) for (auto i: n)
#define vi vector<int>
#define vll vector<ll>
#define prints(n) cout << (n) << " "
#define println(n) cout << (n) << "\n"

const int MOD = 998244353;
// const int MOD = 1e9 + 7;

void solve() {
    ll m, n, k; cin >> m >> n >> k;
    ll s, t; cin >> s >> t;

    vector<vector<pair<ll, ll>>> adj(n, vector<pair<ll, ll>>());

    map<pair<ll, ll>, ll> mp; 
    forn(i, m) {
        ll u, v, w; cin >> u >> v >> w;
        adj[u].push_back({v, w});

        mp[{u, v}] = i;
    }

    set<tuple<ll, ll, ll>> st;
    forn(i, k) {
        ll a, b, c; cin >> a >> b >> c;
        st.insert({a, b, c});
    }

    // Tuple -Dist, Curr, Prev
    priority_queue<tuple<ll, ll, ll>> pq;
    pq.push({0, s, -1});

    ll ans = -1;
    vector<bool> visn(n), vise(m);
    while (!pq.empty()) {
        auto [dist, curr, prev] = pq.top(); pq.pop();
        // prints(dist); prints(curr); println(prev);

        if (curr == t) {
            ans = -dist; break;
        }

        if (visn[curr]) continue;
        visn[curr] = true;

        fora(edge, adj[curr]) {
            ll next = edge.first, cost = edge.second;

            if (!visn[next]) continue;
            if (vise[mp[{curr, next}]]) continue;
            if (st.find({prev, curr, next}) != st.end()) {
                visn[curr] = false; continue;
            }

            pq.push({dist - cost, next, curr});
        }
    }

    println(ans);
}

int32_t main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);

    int t = 1;
    // cin >> t;
    while (t--) solve();

    return 0;
}