#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 100000
#define M 3000000
#define INF 0x3f3f3f3f
int min(int a, int b) { return a < b ? a : b; }
char special[N]; int n;
int ii[M], jj[M], ww[M], m;
int *eh[N], eo[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;
}
int dd[N], rr[N], iq[N + 1], pq[N], 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(int i) {
pq[i] = ++cnt, pq_up(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 dijkstra() {
int i, o;
memset(pq, 0, n * sizeof *pq), cnt = 0;
for (i = 0; i < n; i++)
pq_add(i);
while (cnt) {
i = pq_remove_first();
for (o = eo[i]; o--; ) {
int h = eh[i][o], j = i ^ ii[h] ^ jj[h], d = dd[i] + ww[h];
if (dd[j] > d)
dd[j] = d, rr[j] = rr[i], pq_up(j);
}
}
}
int main() {
int k, h, i, i_, i1, j, j_, j1, w, d, d1, d2, di1, di2, dj1, dj2, ans;
scanf("%d%d%d", &n, &m, &k);
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, &w), i--, j--;
ii[h] = i, jj[h] = j, ww[h] = w;
append(i, h), append(j, h);
}
while (k--) {
scanf("%d", &i), i--;
special[i] = 1;
}
for (i = 0; i < n; i++)
dd[i] = special[i] ? 0 : INF, rr[i] = i;
dijkstra();
d1 = INF, i_ = j_ = -1;
for (h = 0; h < m; h++) {
i = ii[h], j = jj[h];
if (rr[i] != rr[j] && d1 > (d = dd[i] + ww[h] + dd[j]))
d1 = d, i_ = rr[i], j_ = rr[j];
}
for (i = 0; i < n; i++)
dd[i] = special[i] && i != i_ && i != j_ ? 0 : INF, rr[i] = i;
dijkstra();
d2 = INF, i_ = j_ = -1;
for (h = 0; h < m; h++) {
i = ii[h], j = jj[h];
if (rr[i] != rr[j])
d2 = min(d2, dd[i] + ww[h] + dd[j]);
}
ans = d1 + d2;
for (i = 0; i < n; i++)
dd[i] = i == i_ ? 0 : INF, rr[i] = i;
dijkstra();
di1 = di2 = INF, j1 = -1;
for (j = 0; j < n; j++)
if (special[j] && j != i_ && j != j_) {
if (di1 > dd[j])
di2 = di1, di1 = dd[j], j1 = j;
else if (di2 > dd[j])
di2 = dd[j];
}
for (i = 0; i < n; i++)
dd[i] = i == j_ ? 0 : INF, rr[i] = i;
dijkstra();
dj1 = dj2 = INF, i1 = -1;
for (i = 0; i < n; i++)
if (special[i] && i != i_ && i != j_) {
if (dj1 > dd[i])
dj2 = dj1, dj1 = dd[i], i1 = i;
else if (dj2 > dd[i])
dj2 = dd[i];
}
if (i1 != j1)
ans = min(ans, di1 + dj1);
else
ans = min(ans, min(di1 + dj2, di2 + dj1));
printf("%d\n", ans);
return 0;
}
