#include"testlib.h"

#include <set>
#include <utility>
#include <atcoder/dsu>

using ll = long long;
const ll Nmin = 2;
const ll Nmax = 100'000;
const ll Mmin = 1;
const ll Mmax = 100'000;
const ll mod = 998244353;

int main(){
    registerValidation();
    ll N = inf.readLong(Nmin, Nmax);
    inf.readSpace();
    ll M = inf.readLong(Mmin, Mmax);
    inf.readEoln();
    inf.ensuref(N-1 <= M && M <= N*(N-1)/2, "N-1 <= M <= N*(N-1)/2");
    for (ll i = 0; i < N; i++){
        if (i != 0){
            inf.readSpace();
        }
        ll Bi = inf.readLong(0LL, mod-1);
    }
    inf.readEoln();
    std::set<std::pair<ll, ll>> es;
    atcoder::dsu d(N);
    for (ll i = 0; i < M; i++){
        ll ui = inf.readLong(1LL, N);
        inf.readSpace();
        ll vi = inf.readLong(1LL, N);
        inf.readEoln();
        inf.ensuref(ui < vi, "u[i] < v[i]");
        inf.ensuref(!es.contains({ui, vi}), "edges are distinct");
        es.insert({ui, vi});
        ui--, vi--;
        d.merge(ui, vi);
    }
    inf.ensuref((ll)(d.groups().size()) == 1LL, "graph is connected");
    inf.readEof();
}