#include "bits/stdc++.h"

using namespace std;
#ifdef _DEBUG
#define _GLIBCXX_DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define ll long long
#define ll1 1ll
#define ONE 1ll
#define DBG 1
#define rep(i, a, b) for (int i = (a); i < (b); i++)
#define rrep(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define loop(n) rep(loop, (0), (n))
#define all(c) begin(c), end(c)
const int INF =
sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
const double PI = acos(-1);
const double EPS = 1e-9;
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
using pii = pair<int, int>;
// template<class T> ostream &operator<<(ostream &os,T &t){dump(t);return os;}
template <typename T, typename S>
istream &operator>>(istream &is, pair<T, S> &p) {
	is >> p.first >> p.second;
	return is;
}
template <typename T, typename S>
ostream &operator<<(ostream &os, pair<T, S> &p) {
	os << p.first << " " << p.second;
	return os;
}

template <typename T> void printvv(const vector<vector<T>> &v) {
	cerr << endl;
	rep(i, 0, v.size()) rep(j, 0, v[i].size()) {
		if (typeid(v[i][j]).name() == typeid(INF).name() and v[i][j] == INF) {
			cerr << "INF";
		}
		else
			cerr << v[i][j];
		cerr << (j == v[i].size() - 1 ? '\n' : ' ');
	}
	cerr << endl;
}
/*
typedef __int128_t Int;
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
std::ostream::sentry s(dest);
  if (s) {
	__uint128_t tmp = value < 0 ? -value : value;
	char buffer[128];
	char *d = std::end(buffer);
	do {
	  --d;
	  *d = "0123456789"[tmp % 10];
	  tmp /= 10;
	} while (tmp != 0);
	if (value < 0) {
	  --d;
	  *d = '-';
	}
	int len = std::end(buffer) - d;
	if (dest.rdbuf()->sputn(d, len) != len) {
	  dest.setstate(std::ios_base::badbit);
	}
  }
  return dest;
}

__int128 parse(string &s) {
  __int128 ret = 0;
  for (int i = 0; i < s.length(); i++)
	if ('0' <= s[i] && s[i] <= '9')
	  ret = 10 * ret + s[i] - '0';
  return ret;
}
*/

#ifndef _DEBUG
#define printvv(...)
#endif
void YES(bool f) { cout << (f ? "YES" : "NO") << endl; }
void Yes(bool f) { cout << (f ? "Yes" : "No") << endl; }
template <class T> bool chmax(T &a, const T &b) {
	if (a < b) {
		a = b;
		return true;
	}
	return false;
}
template <class T> bool chmin(T &a, const T &b) {
	if (a > b) {
		a = b;
		return true;
	}
	return false;
}
using Weight = int;
using Flow = int;
struct Edge {
	int s, d; Weight w; Flow c;
	Edge() {};
	Edge(int s, int d, Weight w = 1) : s(s), d(d), w(w), c(w) {};
};
bool operator<(const Edge &e1, const Edge &e2) { return e1.w < e2.w; }
bool operator>(const Edge &e1, const Edge &e2) { return e2 < e1; }
inline ostream &operator<<(ostream &os, const Edge &e) { return (os << '(' << e.s << ", " << e.d << ", " << e.w << ')'); }

using Edges = vector<Edge>;
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

void addArc(Graph &g, int s, int d, Weight w = 1) {
	g[s].emplace_back(s, d, w);
}
void addEdge(Graph &g, int a, int b, Weight w = 1) {
	addArc(g, a, b, w);
	addArc(g, b, a, w);
}
struct DisjointSet {
	// ２つのグループを１つにまとめる　と　2つの要素が同じグループに所属しているかどうかを判定する
	vector<int> rank, p, S; // p->parent  S[findSet(v)] ->連結成分の大きさ
	DisjointSet() {}
	DisjointSet(int size) {
		S.resize(size, 1);
		rank.resize(size, 0);
		p.resize(size, 0);
		rep(i, 0, size) makeSet(i);
	}
	void makeSet(int x) {
		p[x] = x;
		rank[x] = 0;
	}
	bool same(int x, int y) { // 判定する
		return findSet(x) == findSet(y);
	}
	void unite(int x, int y) { // 連結するときにはこれを使う
		if (same(x, y))
			return;
		link(findSet(x), findSet(y));
	}
	void link(int x, int y) {
		if (rank[x] > rank[y]) {
			p[y] = x;
		}
		else {
			p[x] = y;
			if (rank[x] == rank[y]) {
				rank[y]++;
			}
		}

		S[x] = S[y] = S[x] + S[y];
	}
	int findSet(int x) {
		if (x != p[x]) {
			p[x] = findSet(p[x]); // path compression
		}
		return p[x];
	}
	int connectedComponentSize(int x) { return S[findSet(x)]; }
};

int kruskal(int N,int K, vector<Edge> &edges) {
	int totalCost = 0;
	sort(all(edges));
	DisjointSet dset(N);
	int k = 0;
	rep(i, 0, edges.size()) {
		Edge e = edges[i];
		if (!dset.same(e.s, e.d)) {
			totalCost += e.w;
			dset.unite(e.s, e.d);
			k++;
			if (k == K - 1)break;
		}
	}
	if (k != K - 1)totalCost = -1;
	return totalCost;
}

signed main(signed argc, char *argv[]) {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(12);

	int N, M; cin >> N >> M;
	int K; cin >> K;
	vector<int>c(N);
	int x = K;
	rep(i, 0, N) {
		cin >> c[i];
		c[i]--;
		if (c[i] == -1)c[i] = x++;
	}

	Edges es;
	loop(M) {
		int a, b, w; cin >> a >> b >> w;
		a--, b--;
		es.eb(c[a], c[b], w);
	}
	cout << kruskal(x,K, es) << endl;
	return 0;
}


Measured memory_bytes: 9324