Kek

#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("fast-math")
#pragma GCC optimize("section-anchors")
#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
#pragma GCC optimize("vpt")
#pragma GCC optimize("rename-registers")
#pragma GCC optimize("move-loop-invariants")
#pragma GCC optimize("unswitch-loops")
#pragma GCC optimize("function-sections")
#pragma GCC optimize("data-sections")
#pragma GCC optimize("branch-target-load-optimize")
#pragma GCC optimize("branch-target-load-optimize2")
#pragma GCC optimize("btr-bb-exclusive")
#pragma GCC optimize("O0")
#include <iostream>
#include <complex>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
#include <random>
using namespace std;

#define F first
#define S second
#define pb push_back
#define pii pair <int, int>
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define reunique(x) (x).resize(std::unique(all(x)) - (x).begin())
#define roflan ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define ld long double
//#define int long long

int is[10500];
int vis[10500];
int dp[10500][600];
vector <pii> g[10500];
void Solve() {
    for (int i = 0; i < 10500; i++) {
        for (int j = 0; j < 600; j++) {
            dp[i][j] = 1e9;
        }
    }
    int k, n, m, U, V;
    cin >> k >> n >> m >> U >> V;
    U--, V--;
    for (int i = 0; i < m; i++) {
        int v, u, w;
        cin >> v >> u >> w;
        if (w > k) continue;
        v--, u--;
        g[v].pb({ u, w });
        g[u].pb({ v, w });
    }
    int l;
    cin >> l;
    for (int i = 0; i < l; i++) {
        int x;
        cin >> x;
        x--;
        is[x] = 1;
    }
    queue <int> q;
    q.push(U);
    dp[U][k] = 0;
    vis[U] = 1;
    is[U] = is[V] = 0;
    while (!q.empty()) {
        auto now = q.front();
        q.pop();
        int v = now;
        for (auto u : g[v]) {
            int to = u.first, need = u.second;
            //if (vis[to]) continue;
            bool fl = 0;
            for (int ost = 0; ost < k; ost++) {
                if (v == U || is[v])
                    dp[v][k] = min(dp[v][k], dp[v][ost]);
                if (need > ost) continue;
                if (dp[v][ost] > 1e10) continue;
                if (dp[to][ost - need] > dp[v][ost]) {
                    dp[to][ost - need] = dp[v][ost];
                    fl = 1;
                }
            }
            if (v == U || is[v]) {
                if (dp[to][k - need] > dp[v][k] + is[v]) {
                    dp[to][k - need] = dp[v][k] + is[v];
                    fl = 1;
                }
            }
            if (fl) {
                q.push(to);
                vis[to] = 1;
            }
        }
    }
    int ans = 1e9;
    for (int i = 0; i <= k; i++) {
        ans = min(ans, dp[V][i]);
    }
    if (ans > 1e8)
        cout << -1 << '\n';
    else
        cout << ans << '\n';
}
signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    Solve();

    return 0;
}