#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<ll, pll> plll;
#define all(x) (x).begin(),(x).end()
#define X first
#define Y second
#define sep ' '
#define endl '\n'
#define debug(x) cerr << #x << ": " << x << endl;
const ll MAXN = 2e3 + 10; // 1e5 ?
const ll MAXL = 1e5 + 10;
const ll INF = 4e18;
vector<int> adj[MAXN];
int from[MAXN], to[MAXN], n, m, t, l, sup_list[MAXL];
ll dist[MAXN][3][MAXN][3], w[MAXN], ans[2][MAXN << 2];
inline int f(int ind, int v) {
return from[ind] + to[ind] - v;
}
inline int edge_side(int ind, int v) {
return from[ind] == v ? 0 : 1;
}
inline void dijkstra(int tv, int tstate) {
dist[tv][tstate][tv][tstate] = 0;
priority_queue<plll, vector<plll>, greater<plll>> pq;
pq.push({0, {tv, tstate}});
while (!pq.empty()) {
int fv = pq.top().Y.X, fstate = pq.top().Y.Y;
ll d_v = pq.top().X;
pq.pop();
if (d_v != dist[tv][tstate][fv][fstate]) continue;
int lst = fv, v = 0;
if (fstate == 0) v = from[lst];
else if (fstate == 1) v = to[lst];
else v = lst, lst = -1;
for (int ind : adj[v]) {
if (ind == lst) continue;
int u = f(ind, v), state = edge_side(ind, u);
ll d_u = d_v + w[ind];
if (d_u < dist[tv][tstate][ind][state]) {
dist[tv][tstate][ind][state] = d_u;
pq.push({d_u, {ind, state}});
}
}
}
}
inline vector<pll> v_states(int v) {
vector<pll> ans;
for (int ind : adj[v])
ans.push_back({ind, edge_side(ind, v)});
return ans;
}
inline void majik(pair<plll, plll>& a, plll b) {
if (b.X < a.X.X) {
a.Y = a.X;
a.X = b;
} else if (b.X < a.Y.X) a.Y = b;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> m >> t >> l;
for (int i = 1; i <= m; i++) {
cin >> from[i] >> to[i] >> w[i];
adj[from[i]].push_back(i);
adj[to[i]].push_back(i);
}
for (int i = 0; i < MAXN; i++)
for (int j = 0; j < 3; j++)
for (int a = 0; a < MAXN; a++)
for (int b = 0; b < 3; b++)
dist[i][j][a][b] = INF;
for (int v = 1; v <= n; v++)
dijkstra(v, 2);
for (int i = 1; i <= m; i++)
dijkstra(i, 1), dijkstra(i, 0);
for (int i = 1; i <= l; i++) cin >> sup_list[i];
while (t--) {
int p, c;
cin >> p >> c;
sup_list[p] = c;
}
ans[1][0] = 0; // !!!
ll fans = INF;
for (int i = 2; i <= l; i++) {
vector<pll> B = v_states(sup_list[i]);
pair<plll, plll> A = {{INF, {INF, INF}}, {INF, {INF, INF}}};
int ind = i & 1;
if (i == 2) A.X = {0, {sup_list[i - 1], 2}};
else {
vector<pll> tmp = v_states(sup_list[i - 1]);
for (int i = 0; i < int(tmp.size()); i++)
majik(A, {ans[ind ^ 1][i], tmp[i]});
}
fill(ans[ind], ans[ind] + int(B.size()), INF);
fans = INF;
for (int i = 0; i < int(B.size()); i++) {
if (A.X.X < INF) ans[ind][i] = min(ans[ind][i], A.X.X + dist[A.X.Y.X][A.X.Y.Y][B[i].X][B[i].Y]);
if (A.Y.X < INF) ans[ind][i] = min(ans[ind][i], A.Y.X + dist[A.Y.Y.X][A.Y.Y.Y][B[i].X][B[i].Y]);
fans = min(fans, ans[ind][i]);
}
/*
if (i == 3) {
for (pll e : B)
cerr << e.X << sep << e.Y << endl;
debug(ans[ind][1])
}
*/ }
cout << (fans == INF ? -1 : fans) << endl;
return 0;
}
