#include <cstdio>

#define INF 1000000000

#define MAXK 50
#define MAXN 500

int d[MAXN+1][MAXN+1], ans[MAXK+1][MAXK+1][MAXN+1], v[MAXN+1];

inline int min2(int a, int b){
    if(a<b) return a;
    else return b;
}

int solve(int st, int dr, int x){
    if(st>dr) return 0;
    if(ans[st][dr][x]!=INF) return ans[st][dr][x];
    for(int i=st; i<=dr; i++) ans[st][dr][x]=min2(ans[st][dr][x], solve(st, i-1, v[i])+solve(i+1, dr, v[i])+d[x][v[i]]);
    return ans[st][dr][x];
}

int main(){
    int k, n, m, x, y, z;
    FILE *fin, *fout;
    fin=fopen("team.in", "r");
    fout=fopen("team.out", "w");
    fscanf(fin, "%d%d%d", &k, &n, &m);
    for(int i=1; i<=n; i++)
        for(int j=1; j<=n; j++)
            if(i!=j)
                d[i][j]=INF;
    for(int i=0; i<m; i++){
        fscanf(fin, "%d%d%d", &x, &y, &z);
        if(z<d[x][y]) d[x][y]=z;
        if(z<d[y][x]) d[y][x]=z;
    }
    for(int k=1; k<=n; k++)
        for(int i=1; i<=n; i++)
            for(int j=1; j<=n; j++)
                if(d[i][k]+d[k][j]<d[i][j])
                    d[i][j]=d[i][k]+d[k][j];
    for(int i=1; i<=k; i++)
        for(int j=1; j<=k; j++)
            for(int p=1; p<=n; p++)
                ans[i][j][p]=INF;
    for(int i=1; i<=k; i++){
        fscanf(fin, "%d", &v[i]);
        ans[i][i][v[i]]=0;
    }
    fprintf(fout, "%d\n", solve(1, k, 1));
    fclose(fin);
    fclose(fout);
    return 0;
}