#include <bits/stdc++.h>
using namespace std;
#define FORU(i, a, b) for(__typeof(b) i = a; i <= b; i ++)
#define FORD(i, b, a) for(__typeof(b) i = b; i >= a; i --)
#define UFOR(i, a, b) for(__typeof(b) i = a; i < b; i ++)
#define DFOR(i, b, a) for(__typeof(b) i = b; i > a; i --)
#define N 100005
#define oo 1000000000000000
#define pb push_back
#define fi first
#define se second
#define ll long long
typedef pair < ll, int > ii;
int n, k, m, s[8];
ll f[1 << 8][N];
vector < ii > a[N];
void read()
{
cin >> n >> k >> m;
FORU(i, 1, k)
cin >> s[i];
int u, v;
ll c;
FORU(i, 1, m)
{
cin >> u >> v >> c;
a[u].pb(ii(c, v));
a[v].pb(ii(c, u));
}
}
void Dijkstra(int mask)
{
priority_queue < ii, vector < ii >, greater < ii > > q;
FORU(i, 1, n)
if(f[mask][i] != oo)
q.push(ii(f[mask][i], i));
while(!q.empty())
{
int u = q.top().se;
ll du = q.top().fi;
q.pop();
if(du != f[mask][u])
continue;
UFOR(i, 0, a[u].size())
{
int v = a[u][i].se;
ll uv = a[u][i].fi;
if(f[mask][v] > f[mask][u] + uv)
{
f[mask][v] = f[mask][u] + uv;
q.push(ii(f[mask][v], v));
}
}
}
}
void solve()
{
FORU(i, 0, 1 << k)
FORU(j, 1, n)
f[i][j] = oo;
FORU(i, 1, k)
f[1 << (i - 1)][s[i]] = 0;
UFOR(x, 1, 1 << k)
{
UFOR(y, 0, x)
{
if((x | y) != x)
continue;
int z = x ^ y;
if(y > z)
continue;
FORU(i, 1, n)
f[x][i] = min(f[x][i], f[y][i] + f[z][i]);
}
Dijkstra(x);
}
ll res = oo;
FORU(i, 1, n)
res = min(res, f[(1 << k) - 1][i]);
if(res == oo)
cout << -1;
else
cout << res;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
read();
solve();
return 0;
}
