import java.io.*;
import java.util.Arrays;
import java.util.Comparator;
import java.util.StringJoiner;
import java.util.StringTokenizer;
import java.util.function.Function;

public class Main {

    static int N, M, K;
    static int[] C;
    static int[] A, B, W;

    public static void main(String[] args) {
        FastScanner sc = new FastScanner(System.in);
        N = sc.nextInt();
        M = sc.nextInt();
        K = sc.nextInt();
        C = sc.nextIntArray(N);
        A = new int[M];
        B = new int[M];
        W = new int[M];
        for (int i = 0; i < M; i++) {
            A[i] = sc.nextInt()-1;
            B[i] = sc.nextInt()-1;
            W[i] = sc.nextInt();
        }

        System.out.println(solve());
    }

    static long solve() {
        int c = K+1;
        for (int i = 0; i < N; i++) {
            if( C[i] == 0 ) C[i] = c++;
        }

        Edge[] E = new Edge[M];
        for (int i = 0; i < M; i++) {
            E[i] = new Edge(C[A[i]], C[B[i]], W[i]);
        }

        Arrays.sort(E, Comparator.comparingInt(e -> e.w));

        UnionFind uf = new UnionFind(c+10);
        long ans = 0;
        int cnt = 0;
        for (Edge e : E) {
            if( !uf.isSame(e.a, e.b) ) {
                ans += e.w;
                uf.unite(e.a, e.b);
                cnt++;
            }
            if( cnt == K-1 ) break;
        }
        return cnt == K-1 ? ans : -1;
    }

    static class UnionFind {

        private final int[] parent;
        private final int[] rank;

        public UnionFind(int n) {
            parent = new int[n];
            rank = new int[n];
            for (int i = 0; i < n; i++) {
                parent[i] = i;
                rank[i] = 0;
            }
        }

        public int root(int i) {
            if( parent[i] == i ) {
                return i;
            } else {
                return parent[i] = root(parent[i]);
            }
        }

        public void unite(int i, int j) {
            int ri = root(i);
            int rj = root(j);
            if( ri == rj ) return;

            if( rank[ri] < rank[rj] ) {
                parent[ri] = rj;

            } else {
                parent[rj] = ri;
                if( rank[ri] == rank[rj] ) {
                    rank[ri]++;
                }
            }
        }

        public boolean isSame(int a, int b) {
            return root(a) == root(b);
        }
    }

    static class Edge {
        final int a, b, w;

        public Edge(int a, int b, int w) {
            this.a = a;
            this.b = b;
            this.w = w;
        }

        int opposite(int x) {
            return a == x ? b : a;
        }
    }

    @SuppressWarnings("unused")
    static class FastScanner {
        private BufferedReader reader;
        private StringTokenizer tokenizer;

        FastScanner(InputStream in) {
            reader = new BufferedReader(new InputStreamReader(in));
            tokenizer = null;
        }

        String next() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

        String nextLine() {
            if (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    return reader.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken("\n");
        }

        long nextLong() {
            return Long.parseLong(next());
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        int[] nextIntArray(int n, int delta) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt() + delta;
            return a;
        }

        long[] nextLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
    }

    static <A> void writeLines(A[] as, Function<A, String> f) {
        PrintWriter pw = new PrintWriter(System.out);
        for (A a : as) {
            pw.println(f.apply(a));
        }
        pw.flush();
    }

    static void writeLines(int[] as) {
        PrintWriter pw = new PrintWriter(System.out);
        for (int a : as) pw.println(a);
        pw.flush();
    }

    static void writeLines(long[] as) {
        PrintWriter pw = new PrintWriter(System.out);
        for (long a : as) pw.println(a);
        pw.flush();
    }

    static int max(int... as) {
        int max = Integer.MIN_VALUE;
        for (int a : as) max = Math.max(a, max);
        return max;
    }

    static int min(int... as) {
        int min = Integer.MAX_VALUE;
        for (int a : as) min = Math.min(a, min);
        return min;
    }

    static void debug(Object... args) {
        StringJoiner j = new StringJoiner(" ");
        for (Object arg : args) {
            if (arg instanceof int[]) j.add(Arrays.toString((int[]) arg));
            else if (arg instanceof long[]) j.add(Arrays.toString((long[]) arg));
            else if (arg instanceof double[]) j.add(Arrays.toString((double[]) arg));
            else if (arg instanceof Object[]) j.add(Arrays.toString((Object[]) arg));
            else j.add(arg.toString());
        }
        System.err.println(j.toString());
    }
}


Measured memory_bytes: 50252