#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;
#define FI first
#define SE second
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))

const string NO = "Impossible";
struct SizeAwareUnionFind
{
    vector<int> par, cou;
    SizeAwareUnionFind(int N) : par(N), cou(N) { REP(i, N) par[i] = i, cou[i] = 1; }
    int find(int x) { return (par[x] == x) ? x : (par[x] = find(par[x])); }
    void unite(int x, int y) {
        x = find(x), y = find(y); if (x == y) return;
        if (cou[x] < cou[y]) swap(x, y); 
        par[y] = x, cou[x] += cou[y];
    }
    int count(int x) { return cou[find(x)]; }
    bool same(int x, int y) { return find(x) == find(y); }
};

int N, M;
int main()
{
    cin >> N >> M;
    vector<lint> a(N), x(M), y(M);
    SizeAwareUnionFind uf(N);
    cin >> a;
    REP(i, M)
    {
        cin >> x[i] >> y[i];
        uf.unite(x[i], y[i]);
    }
    map<int, vector<int>> tree2vals;
    REP(i, N) tree2vals[uf.find(i)].push_back(a[i]);
    for (auto &pa : tree2vals) sort(ALL(pa.second));

    int Ntree = tree2vals.size();
    if (Ntree == 1)
    {
        cout << 0 << endl;
        return 0;
    }
    lint ans = 0;
    map<int, int> tree_cou;

    priority_queue<pint, vector<pint>, greater<pint>> pq;
    int n_edge = 0;
    for (auto &pa : tree2vals)
    {
        ans += *pa.second.begin();
        pa.second.erase(pa.second.begin());
        tree_cou[pa.first]++;
        n_edge++;
        for (auto v : pa.second) pq.push(pint(v, pa.first));
    }

    while (!pq.empty() and n_edge < (N - 1 - M) * 2)
    {
        pint pa = pq.top();
        pq.pop();
        if (tree_cou[pa.second] < Ntree)
        {
            tree_cou[pa.second]++;
            ans += pa.first;
            n_edge++;
        }
    }

    if (n_edge < (N - 1 - M) * 2)
    {
        cout << NO << endl;
    }
    else
    {
        cout << ans << endl;
    }
}


Measured memory_bytes: 17408