#include<bits/stdc++.h>
using namespace std;
#define fr first
#define sc second
#define pb push_back
#define mp make_pair
#define int long long

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n, r, m;
    cin >> n >> r >> m;
    vector<pair<int,int>>adj[n];
    vector<int>delta[n][n][n];
    int mat[n][n][n];
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            for (int e = 0; e < n; e++){
                mat[i][j][e] = (int)1e18;
                delta[i][j][e] = {(int)1e18};
            }
        }
    }
    for (int i = 0; i < r; i++){
        int a,b, c;
        cin >> a >> b >> c;
        --a,--b;
        adj[a].pb(mp(b,c));
        adj[b].pb(mp(a,c));
    }
    vector<int>kuponi(m);
    for (int i = 0; i < m; i++)cin >> kuponi[i];
    sort(kuponi.rbegin(), kuponi.rend());
    int sum = 0;
    for (int i = 0; i < n; i++){
        for (auto j : adj[i]){
            mat[i][j.fr][1] = max(0LL, j.sc - kuponi[0]);
            mat[j.fr][i][1] = max(0LL, j.sc - kuponi[0]);
            delta[i][j.fr][1] = {j.sc};
            delta[j.fr][i][1] = {j.sc};
        }
    }


    for(int e1 = 0; e1 < n; e1++){
            for (int e2 = 0; e2 + e1 < n; e2++){
                for (int k = 0; k < n; k++){
                    for (int a = 0; a < n; a++){
                        for (int b = 0; b < n; b++){
                            vector<int>nova = delta[a][k][e1];
                            for (auto el : delta[k][b][e2])nova.pb(el);
                            sort(nova.rbegin(),nova.rend());
                            int tot = 0;
                            for (int p = 0; p < (int)nova.size(); p++){
                                if (p < m)tot += max(0LL, nova[p] - kuponi[p]);
                                else tot += nova[p];
                           }
                           if (mat[a][b][e1 + e2] > tot){
                           mat[a][b][e1+e2] = tot;
                           delta[a][b][e1+e2] = nova;
                           }
                       }
                  }
             }
         }
    }
    for (int i = 0; i < n; i++){
        for (int j = i + 1; j < n; j++){
        int best = (int)1e18;
        for (int p = 0; p < n; p++){
            best = min(best, mat[i][j][p]);
        }
        sum += best;
      }
    }
    cout<<sum;
    return 0;
}