#include <bits/stdc++.h>
#define maxn 55
#define maxv 505

class InParser {
private:
	FILE *fin;
	char *buff;
	int sp;

	char read_ch() {
		++sp;
		if (sp == 4096) {
			sp = 0;
			fread(buff, 1, 4096, fin);
		}
		return buff[sp];
	}

public:
	InParser(const char* nume) {
		fin = fopen(nume, "r");
		buff = new char[4096]();
		sp = 4095;
	}

	InParser& operator >> (int &n) {
		char c;
		while (!isdigit(c = read_ch()) && c != '-');
		int sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}

	InParser& operator >> (long long &n) {
		char c;
		n = 0;
		while (!isdigit(c = read_ch()) && c != '-');
		long long sgn = 1;
		if (c == '-') {
			n = 0;
			sgn = -1;
		} else {
			n = c - '0';
		}
		while (isdigit(c = read_ch())) {
			n = 10 * n + c - '0';
		}
		n *= sgn;
		return *this;
	}
};

InParser fin("team.in");
std::ofstream fout("team.out");

int x[maxn];
int dist[maxv][maxv];
int dest[maxn];
int dp[maxn][maxn][maxn];

void computeMinDist(int n){
    int i, j, k;
    for (k=1; k<=n; k++){
        for (i=1; i<=n; i++){
            if (i == k) continue;
            for (j=1; j<=n ; j++){
                if (j == k or j == i) continue;
                if (dist[i][k] == -1 or dist[k][j] == -1) continue;
                if (dist[i][j] == -1) dist[i][j] = 1e9;

                dist[i][j] = std::min (dist[i][j], dist[i][k] + dist[k][j]);
            }
        }
    }
}

int main()
{
    int n, V, E, src, dst, cost, i, j, k, u;
    fin >> n >> V >> E;

    for (i=1; i<=V; i++)
    for (j=1; j<=V; j++)
        dist[i][j] = -1;

    for (i=1; i<=V; i++)
        dist[i][i] = 0;

    for (i=0; i<E; i++) {
        fin >> src >> dst >> cost;
        dist[src][dst] = cost;
        dist[dst][src] = cost;
    }



    /*
    for (i=1; i<=V; i++, fout << '\n')
        for (j=1; j<=V; j++)
        fout << dist[i][j] << ' ';
        */

    for (i=1; i<=n; i++)
        fin >> dest[i];
    computeMinDist(V);

    for (i=1; i<=n; i++)
        dp[i][i][i] = 0;

    for (int l=0; l<=n; l++)
    for (i=1; i<=n; i++){
        j = i + l;
        for (k=1; k<=n; k++){
            if (k == i and k == j)
            continue;
            dp[i][j][k] = 1e9;
            for (u=i; u<=j; u++){
                //std::cout << dp[i][u-1][u] << ' ' << dp[u+1][j][i]  << ' ' << dist[dest[u]][dest[k]] << dp[i][u-1][u] + dp[u+1][j][i] + dist[dest[u]][dest[k]] << '\n';
                //std::cout << std::min (dp[i][j][k], dp[i][u-1][u] + dp[u+1][j][u] + dist[dest[u]][dest[k]]) << '\n';
                dp[i][j][k] = std::min (dp[i][j][k], dp[i][u-1][u] + dp[u+1][j][u] + dist[dest[u]][dest[k]]);
            }
        }
    }



    int ans = 1e9;
    for (i=1; i<=n; i++)
    ans = std::min (ans, dp[1][n][i] + dist[1][dest[i]]);

    fout << ans;

    return 0;
}