#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;
    }

    map<pair<int, int>, set<int>> forb;
    forn(i, k) {
        ll a, b, c; cin >> a >> b >> c;
        if (forb.find({a, b}) == forb.end()) forb[{a, b}] = set<int>();
        forb[{a, b}].insert(c);
    }

    priority_queue<pair<int, pair<int, int>>> pq;

    pq.push({0, {-1, s}});

    set<int> vis[n+5];

    while (!pq.empty()) {
        pair<int, pair<int, int>> p = pq.top();
        int w = p.first;
        int prev = p.second.first;
        int cur = p.second.second;
        pq.pop();

        if (cur == t) {
            cout << -w << '\n';
            return;
        }

        if (vis[cur].count(prev) || vis[cur].count(-1)) {
            continue;
        }
        if (forb.count({prev, cur})) {
            vis[cur].insert(prev);
        }
        else {
            vis[cur].insert(-1);
        }

        set<int> curforb = forb[{prev, cur}];
        for(auto x: adj[cur]) {
            if (curforb.count(x.first)) continue;
            pq.push({w - x.second, {cur, x.first}});
        }
    }
    
}

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

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

    return 0;
}