#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <set>
#include <map>
#include <queue>

//#define int long long

#define vi vector<int>
#define vec vector

using namespace std;

double get() {
    return ((double)rand()) / RAND_MAX;
}
const int MOD = 1000000007;

int fact[1000010], inv[1000010];

int C(int k, int n) {
    return fact[n] * inv[k] % MOD * inv[n - k] % MOD;
}

int binpow(int a, int b) {
    if (!b) return 1;
    int x = binpow(a, b >> 1);
    if (b & 1) return (((x * x) % MOD) * a) % MOD;
    return((x * x) % MOD);
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int n, m, s, k;
    cin >> n >> m >> s >> k;
    s--;
    vi x(k);
    for (auto& e : x) cin >> e, --e;
    vi dm(n);
    for (auto& e : dm) cin >> e;
    vec<vec<pair<int, int>>> g(n);
    vec<vi> dp(n, vi(1051, 2e9));
    while (m--) {
        int f, t, s;
        cin >> f >> t >> s;
        --f; --t;
        g[f].push_back({ t, s });
        g[t].push_back({ f, s });
    }
    queue<pair<pair<int, int>, int>> q;
    q.push({ { s, dm[s] }, 0 });
    while (q.size()) {
        auto cur = q.front();
        q.pop();
        for (auto& e : g[cur.first.first]) {
            if (e.second <= cur.first.second) {
                int nd = max(cur.first.second - e.second, dm[e.first]);
                if (dp[e.first][nd] > cur.second + e.second) {
                    dp[e.first][nd] = cur.second + e.second;
                    q.push({ {e.first, nd}, cur.second + e.second });
                }
            }
        }
    }
    int ans = 2e9;
    for (auto& e : x) {
        for (int i = 0; i < 1051; ++i)
            ans = min(ans, dp[e][i]);
    }
    if (ans != 1e9)
        cout << ans;
    else cout << 0;

}

// N
// Q L R X
// N
//