#include<algorithm>
#include<bitset>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<ctime>
#include<deque>
#include<fstream>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<unordered_map>
#include<unordered_set>
#include<utility>
#include<vector>

using namespace std;

#define dbg(x) (cout<<#x<<" = "<<(x)<<'\n')
#ifdef HOME
const string inputFile = "input.txt";
const string outputFile = "output.txt";
#else
const string problemName = "team";
const string inputFile = problemName + ".in";
const string outputFile = problemName + ".out";
#endif

typedef long long int lld;
typedef pair<int, int> PII;
typedef pair<int, lld> PIL;
typedef pair<lld, int> PLI;
typedef pair<lld, lld> PLL;

const int INF = (1LL << 29) - 1;
const lld LINF = (1LL << 62) - 1;
const int dx[] = {1, 0, -1, 0, 1, -1, 1, -1};
const int dy[] = {0, 1, 0, -1, 1, -1, -1, 1};

int N, M, P;
int DP[55][55][505];
bool viz[55][55][505];
int C[505][505];
int dest[55];
vector<PII> V[505];
priority_queue<PII, vector<PII>, greater<PII> > PQ;

void dijkstra(int x, int *D) {
    int i, y, z;
    bool viz[505];

    for(i = 1; i <= N; i++) {
        D[i] = INF;
        viz[i] = 0;
    }

    D[x] = 0;
    PQ.push(make_pair(0, x));

    while(!PQ.empty()) {
        x = PQ.top().second;
        PQ.pop();

        if(viz[x])
            continue;

        viz[x] = 1;

        for(auto nod : V[x]) {
            y = nod.first;
            z = nod.second;
            if(D[x] + z < D[y]) {
                D[y] = D[x] + z;
                PQ.push(make_pair(D[y], y));
            }
        }
    }
}

int solve(int i, int j, int x) {
    if(i > j)
        return 0;

    if(viz[i][j][x])
        return DP[i][j][x];

    int k, ans = INF;

    for(k = i; k <= j; k++)
        ans = min(ans, solve(i, k - 1, dest[k]) + solve(k + 1, j, dest[k]) + C[x][dest[k]]);

    viz[i][j][x] = 1;
    DP[i][j][x] = ans;

    return DP[i][j][x];
}

int main() {
    int i, j, k, x, y, z;

#ifndef ONLINE_JUDGE
    freopen(inputFile.c_str(), "r", stdin);
    freopen(outputFile.c_str(), "w", stdout);
#endif

    scanf("%d%d%d", &P, &N, &M);

    while(M--) {
        scanf("%d%d%d", &x, &y, &z);
        V[x].push_back(make_pair(y, z));
        V[y].push_back(make_pair(x, z));
    }

    for(i = 1; i <= P; i++)
        scanf("%d", &dest[i]);

    for(i = 1; i <= N; i++)
        dijkstra(i, C[i]);

    printf("%d\n", solve(1, P, 1));

    return 0;
}