// May this submission get accepted!

#pragma GCC optimize ("O3")
#pragma GCC target ("tune=native")
#pragma GCC target ("avx")

#include <bits/stdc++.h>

// 汎用マクロ
#define ALL_OF(x) (x).begin(), (x).end()
#define REP(i,n) for (long long i=0, i##_len=(n); i<i##_len; i++)
#define RANGE(i,is,ie) for (long long i=(is), i##_end=(ie); i<=i##_end; i++)
#define DSRNG(i,is,ie) for (long long i=(is), i##_end=(ie); i>=i##_end; i--)
#define UNIQUE(v) { sort((v).begin(), (v).end()); (v).erase(unique((v).begin(), (v).end()), (v).end()); }
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; }
#define INF 0x7FFFFFFF
#define LINF 0x7FFFFFFFFFFFFFFFLL
#define Yes(q) ((q) ? "Yes" : "No")
#define YES(q) ((q) ? "YES" : "NO")
#define Possible(q) ((q) ? "Possible" : "Impossible")
#define POSSIBLE(q) ((q) ? "POSSIBLE" : "IMPOSSIBLE")
#define DUMP(q) cerr << "[DEBUG] " #q ": " << (q) << " at " __FILE__ ":" << __LINE__ << endl
#define DUMPALL(q) { cerr << "[DEBUG] " #q ": ["; REP(i, (q).size()) { cerr << (q)[i] << (i == i_len-1 ? "" : ", "); } cerr << "] at " __FILE__ ":" << __LINE__ << endl; }
template<class T> T gcd(const T &a, const T &b) { return a < b ? gcd(b, a) : b ? gcd(b, a % b) : a; }
template<class T> T lcm(const T &a, const T &b) { return a / gcd(a, b) * b; }

// gcc拡張マクロ
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll

// エイリアス
#define DANCE_ long
#define ROBOT_ unsigned
#define HUMAN_ signed
#define CHOKUDAI_ const
using  ll = DANCE_ HUMAN_ DANCE_;
using ull = DANCE_ ROBOT_ DANCE_;
using cll = DANCE_ DANCE_ CHOKUDAI_;
using  ld = long double;
using namespace std;

// モジュール
// Union-Find モジュール
struct union_find {
    vector<ull> par;
    vector<ull> num;
    union_find(ull n) : par(n, 0), num(n, 1) { iota(ALL_OF(par), 0); }
    ull root(ull i) { return par[i] == i ? i : (par[i] = root(par[i])); }
    bool same(ull i, ull j) { return root(i) == root(j); }
    void unite(ull i, ull j) {
        ull ri = root(i);
        ull rj = root(j);
        if (ri != rj) {
            if (num[ri] > num[rj]) swap(ri, rj);
            par[ri] = rj;
            num[rj] += num[ri];
        }
    }
};

// 処理内容
int main() {
    
    ll n, m; cin >> n >> m;
    vector<ll> a(n), x(m), y(m);
    // already 0-indexed
    REP(i, n) cin >> a[i];
    REP(i, m) cin >> x[i] >> y[i];

    ll reme = n - m - 1;
    if (reme * 2 > n) {
        cout << "Impossible\n";
        return 0;
    }

    if (reme == 0) {
        cout << 0 << endl;
        return 0;
    }

    
    // 連結
    union_find uf(n);
    REP(i, m) uf.unite(x[i], y[i]);
    REP(i, n) uf.root(i);
    vector<ull> unq = uf.par;
    UNIQUE(unq);
    if (unq.size() == 1) {
        cout << 0 << endl;
        return 0;
    }
    map<ll, ll> ufm;
    REP(i, unq.size()) ufm[unq[i]] = i;
    vector<ll> tid(n); // 連結成分ごとのID
    REP(i, n) tid[i] = ufm[uf.par[i]];

    ll remv = reme * 2;
    ll ans = 0;
    vector<vector<ll>> r(unq.size());
    vector<ll> r2; r2.reserve(n);
    REP(i, n) r[ufm[uf.root(i)]].push_back(i);
    REP(i, unq.size()) {
        sort(ALL_OF(r[i]), [&](ll i, ll j) {
            return a[i] < a[j];
        });
        ans += a[r[i].front()];
        if (--remv < 0) {
            cout << "Impossible" << endl;
        }
        RANGE(j, 1, r[i].size() - 1) {
            r2.push_back(r[i][j]);
        }
    }
    sort(ALL_OF(r2), [&](ll i, ll j) {
        return a[i] < a[j];
    });
    REP(i, r2.size()) if (--remv >= 0) {
        ans += a[r2[i]];
    } else break;
    
    cout << ans << endl;

}

Measured memory_bytes: 11648