#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 2000
#define M 2000
#define L 100000
#define INF 0x3f3f3f3f3f3f3f3fLL
long long min(long long a, long long b) { return a < b ? a : b; }
int ij[M * 2], cc[M], m;
int *eh[N], eo[N], n;
void append(int i, int h) {
int o = eo[i]++;
if (o >= 2 && (o & o - 1) == 0)
eh[i] = (int *) realloc(eh[i], o * 2 * sizeof *eh[i]);
eh[i][o] = h;
}
long long *dd_; int iq[M * 2 + 1], pq[M * 2], cnt;
int lt(int i, int j) { return dd_[i] < dd_[j]; }
int p2(int p) {
return (p *= 2) > cnt ? 0 : (p < cnt && lt(iq[p + 1], iq[p]) ? p + 1 : p);
}
void pq_up(int i) {
int p, q, j;
for (p = pq[i]; (q = p / 2) && lt(i, j = iq[q]); p = q)
iq[pq[j] = p] = j;
iq[pq[i] = p] = i;
}
void pq_dn(int i) {
int p, q, j;
for (p = pq[i]; (q = p2(p)) && lt(j = iq[q], i); p = q)
iq[pq[j] = p] = j;
iq[pq[i] = p] = i;
}
void pq_add_last(int i) {
iq[pq[i] = ++cnt] = i;
}
int pq_remove_first() {
int i = iq[1], j = iq[cnt--];
if (j != i)
pq[j] = 1, pq_dn(j);
pq[i] = 0;
return i;
}
void solve(long long *dd, int u) {
static int kk[N];
int h, i, o;
memset(dd, 0x3f, m * 2 * sizeof *dd), memset(kk, 0, n * sizeof *kk);
dd_ = dd, dd[u] = cc[u >> 1], pq_add_last(u);
while (cnt) {
h = pq_remove_first(), i = ij[h ^ 1];
if (kk[i] < 2) {
kk[i]++;
for (o = eo[i]; o--; ) {
int h_ = eh[i][o];
long long d = dd[h] + cc[h_ >> 1];
if ((h ^ h_) != 1 && dd[h_] > d) {
if (dd[h_] == INF)
pq_add_last(h_);
dd[h_] = d, pq_up(h_);
}
}
}
}
}
int main() {
static long long dd[M * 2][M * 2], dp[M * 2], dq[M * 2];
static int uu1[M * 2][N], uu2[M * 2][N], ii[L];
int q, l, g, h, i, j, t, t1, t2, u, v;
long long ans;
scanf("%d%d%d%d", &n, &m, &q, &l);
for (i = 0; i < n; i++)
eh[i] = (int *) malloc(2 * sizeof *eh[i]);
for (h = 0; h < m; h++) {
scanf("%d%d%d", &i, &j, &cc[h]), i--, j--;
ij[h << 1 | 0] = i, ij[h << 1 | 1] = j;
append(i, h << 1 | 0), append(j, h << 1 | 1);
}
for (u = 0; u < m * 2; u++)
solve(dd[u], u);
for (g = 0; g < l; g++)
scanf("%d", &ii[g]), ii[g]--;
while (q--) {
scanf("%d%d", &g, &i), g--, i--;
ii[g] = i;
}
for (v = 0; v < m * 2; v++) {
memset(uu1[v], -1, n * sizeof *uu1[v]), memset(uu2[v], -1, n * sizeof *uu2[v]);
for (u = 0; u < m * 2; u++)
if (dd[u][v] != INF) {
i = ij[u];
if (uu1[v][i] == -1 || dd[uu1[v][i]][v] > dd[u][v])
uu2[v][i] = uu1[v][i], uu1[v][i] = u;
else if (uu2[v][i] == -1 || dd[uu2[v][i]][v] > dd[u][v])
uu2[v][i] = u;
}
}
for (g = 0; g + 1 < l; g++) {
i = ii[g], j = ii[g + 1];
memset(dq, 0x3f, m * 2 * sizeof *dq);
t1 = t2 = -1;
for (t = 0; t < m * 2; t++)
if (dp[t] != INF) {
if (t1 == -1 || dp[t1] > dp[t])
t2 = t1, t1 = t;
else if (t2 == -1 || dp[t2] > dp[t])
t2 = t;
}
for (v = 0; v < m * 2; v++)
if (ij[v ^ 1] == j && (u = uu1[v][i]) != -1) {
if (g == 0)
dq[v] = min(dq[v], dd[u][v]);
else {
if (t1 != -1 && (t1 ^ u) != 1)
dq[v] = min(dq[v], dp[t1] + dd[u][v]);
else if (t2 != -1)
dq[v] = min(dq[v], dp[t2] + dd[u][v]);
if ((u = uu2[v][i]) != -1) {
if (t1 != -1 && (t1 ^ u) != 1)
dq[v] = min(dq[v], dp[t1] + dd[u][v]);
else if (t2 != -1)
dq[v] = min(dq[v], dp[t2] + dd[u][v]);
}
}
}
memcpy(dp, dq, m * 2 * sizeof *dq);
}
ans = INF;
for (v = 0; v < m * 2; v++)
ans = min(ans, dp[v]);
printf("%lld\n", ans == INF ? -1 : ans);
return 0;
}
