#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define svec(v) cout<<#v<<":";rep(kbrni,v.size())cout<<" "<<v[kbrni];cout<<endl
#define sset(s) cout<<#s<<":";each(kbrni,s)cout<<" "<<kbrni;cout<<endl
#define smap(m) cout<<#m<<":";each(kbrni,m)cout<<" {"<<kbrni.first<<":"<<kbrni.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

class UF {
private:
    int sz; vector<int> par,nrank;
public:
    UF(){}
    UF(int node_size){ sz = node_size; par.resize(sz),nrank.resize(sz); rep(i,sz){ par[i] = i; nrank[i] = 0; } }
    int find(int x){ if(par[x] == x){ return x; }else{ return par[x] = find(par[x]); } }
    void unite(int x,int y)
    { x = find(x),y = find(y); if(x == y) return;
    	if(nrank[x] < nrank[y]){ par[x] = y; }else{ par[y] = x; if(nrank[x] == nrank[y]) nrank[x]++; } }
    bool same(int x,int y){ return find(x) == find(y); }
};

struct edge
{
    int from,to;
    ll cost;
    bool operator< (const edge& another) const {
        return cost < another.cost;
    }
};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n,m,K;
    cin >> n >> m >> K;
    vi c(n);
    int id = K;
    rep(i,n){
        cin >> c[i];
        if(c[i] == 0){
            c[i] = id++;
        }else{
            --c[i];
        }
    }
    UF uf(n+K);
    vector<edge> w(m);
    rep(i,m){
        int a,b,d;
        cin >> a >> b >> d;
        --a,--b;
        w[i] = (edge){c[a],c[b],d};
    }
    sort(all(w));
    set<int> st;
    int hen = 0;
    ll ans = 0;
    rep(i,m){
        edge& e = w[i];
        int a = w[i].from, b = w[i].to;
        if(!uf.same(a,b)){
            uf.unite(a,b);
            hen++;
            ans += w[i].cost;
        }
        if(hen == K-1){
            break;
        }
    }
    if(hen == K-1){
        cout << ans << "\n";
    }else{
        cout << "-1\n";
    }
    return 0;
}
