#include <bits/stdc++.h>

#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 reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit32(x) (1 << (x))
#define bit64(x) (1ll << (x))

using namespace std;

using i32 = int;
using i64 = long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); return a / gcd(a, b) * b; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }

struct UnionFind {
  vector<int> data;
  UnionFind(int n) {
    data.assign(n, -1);
  }
  int root(int k) {
    if (data[k] < 0) return k;
    return data[k] = root(data[k]);
  }
  bool unite(int x, int y) {
    x = root(x), y = root(y);
    if (x == y) return false;
    if (data[x] > data[y]) swap(x, y);
    data[x] += data[y];
    data[y] = x;
    return true;
  }
  int size(int k) {
    return -data[root(k)];
  }
};

void pqmerge(pqasc<int> &q1, pqasc<int> &q2) {
  if (q1.size() > q2.size()) {
    while (q2.size()) {
      q1.emplace(q2.top());
      q2.pop();
    }
  } else {
    while (q1.size()) {
      q2.emplace(q1.top());
      q1.pop();
    }
    swap(q1, q2);
  }
}

void solve() {
  int n, m;
  cin >> n >> m;
  if (n - 2 * m - 2 > 0) {
    cout << "Impossible" << endl;
    return;
  }
  if (n - 1 == m) {
    cout << 0 << endl;
    return;
  }
  vi32 a(n);
  cin >> a;
  vector<pqasc<int>> qs(n);
  rep(i, n) {
    qs[i].emplace(a[i]);
  }
  auto uf = UnionFind(n);
  rep(i, m) {
    int x, y;
    cin >> x >> y;

    int rx = uf.root(x);
    int ry = uf.root(y);
    pqmerge(qs[rx], qs[ry]);

    uf.unite(rx, ry);
    int root = uf.root(rx);
    if (root == ry) {
      swap(qs[ry], qs[rx]);
    }
  }
  i64 ans = 0;

  int t = 2 * (n - m - 1);
  vi32 rest;
  {
    vi32 f(n);
    rep(i, n) if (!f[uf.root(i)]) {
      int root = uf.root(i);

      ans += qs[root].top();
      t--;
      qs[root].pop();

      while (qs[root].size()) {
        rest.emplace_back(qs[root].top());
        qs[root].pop();
      }
      f[root] = 1;
    }
  }
  sort(all(rest));
  rep(i, t) ans += rest[i];

  cout << ans << endl;
}


Measured memory_bytes: 9464