#include<bits/stdc++.h>
using namespace std;
#define rep(i, l, n) for(int i = l; i < n; i++)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
#define endl '\n'

#ifdef LOCAL
#define debug(args...) LKJ("\033[1;32m["#args"]\033[0m", args)
template<class I> void LKJ(I&&x) { cerr << x << endl; }
template<class I, class ...T> void LKJ(I&&x, T&&...t)
{ cerr << x << ", ", LKJ(t...);}
#else 
#define debug(...) ((void)0)
#endif

set<pair<pii,int > > fb;
vector<pii> g[30010];
map<pii, int> dis;

int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    int n, m, k, s, t;
    cin >> m >> n >> k;
    cin >> s >> t;
    rep(i, 0, m){
        int x, y, w;
        cin >> x >> y >> w;
        
        g[x].push_back({y, w});
        //g[y].push_back({x, w});
    }
    rep(i, 0, k){
        int x, y, z;
        cin >> x >> y >> z;
        //--x, --y, --z;
        fb.insert({{x, y}, z});
    }
    dis[make_pair(-1, s)] = 0;
    priority_queue<pair<int, pii>, vector<pair<int, pii>>, greater<pair<int, pii>> > pq;
    pq.push({0, {-1, s}});
    while(!pq.empty()){
        auto pt = pq.top();pq.pop();
        if(dis[pt.second] < pt.first) continue;
        for(auto ptt: g[pt.second.second]){
            if(fb.count({pt.second, ptt.first})) continue;
            if((!dis.count({pt.second.second, ptt.first})) || dis[make_pair(pt.second.second, ptt.first)] > pt.first + ptt.second){
                dis[make_pair(pt.second.second, ptt.first)] = pt.first + ptt.second;
                pq.push({dis[make_pair(pt.second.second, ptt.first)], {pt.second.second, ptt.first}});
            }
        }
    }
    int ans = 1e9;
    for(auto tmp: dis)
        if(tmp.first.second == t)ans = min(ans, tmp.second);
    cout << ans << endl;
    return 0;
}