import java.util.*;
import java.io.*;

@SuppressWarnings("unused")
public class Main {
    FastScanner in;
    PrintWriter out;
    int MOD = (int)1e9+7;
    long ceil(long a, long b){return (a + b - 1) / b;}
    long gcd(long a, long b){return b == 0 ? a : gcd(b, a % b);}
    long lcm(long a, long b){return a / gcd(a, b) * b;}
    
    void solve(){
        int N = in.nextInt(), M = in.nextInt();
        int[][] aidx = new int[N][2];
        for(int i = 0; i < N; i++){
            aidx[i][0] = in.nextInt();
            aidx[i][1] = i;
        }
        Arrays.sort(aidx, (e1, e2)->Integer.compare(e1[0], e2[0]));
        UnionFind uf = new UnionFind(N);
        for(int i = 0; i < M; i++){
            int x = in.nextInt(), y = in.nextInt();
            uf.unite(x, y);
        }
        
        if(uf.group == 1){
            out.println("0");
            return;
        }
        
        long sum = 0;
        boolean[] visited = new boolean[N];
        ArrayList<Integer> list = new ArrayList<>();
        for(int[] e : aidx){
            if(!visited[uf.root(e[1])]){
                visited[uf.root(e[1])] = true;
                sum += e[0];
            }else{
                list.add(e[0]);
            }
        }
        
        int num = (uf.group() - 1) * 2 - uf.group();
        if(list.size() < num){
            out.println("Impossible");
        }else{
            for(int i = 0; i < num; i++) sum += list.get(i);
            out.println(sum);
        }
    }
    
    class UnionFind{
        private int[] par;
        private int[] rank;
        private int[] size;
        private int group;
        
        UnionFind(int n){
            par = new int[n];
            rank = new int[n];
            size = new int[n];
            group = n;
            for(int i = 0; i < n; i++){
                par[i] = i;
                rank[i] = 0;
                size[i] = 1;
            }
        }
        
        //ランクの小さいほうにつなげる
        boolean unite(int x, int y){
            x = root(x);
            y = root(y);
            if(x == y) return false;
            
            if(rank[x] < rank[y]){
                int tmp = x; x = y; y = tmp;
            }
            
            //y(のroot)をx(のroot)の下にくっつける
            //yのほうが重くなる(ポテンシャルが高くなる)
            if(rank[x] == rank[y]) rank[x]++;
            group--;
            par[y] = x;
            size[x] += size[y];
            
            return true;
        }
        
        //経路圧縮しながらrootを求める
        int root(int x){
            if(par[x] == x){
                return x;
            }else{
                int f = root(par[x]);
                return par[x] = f;
            }
        }
        
        int rank(int x){return rank[root(x)];}
        int size(int x){return size[root(x)];}
        int group(){return this.group;}
        boolean isSame(int x, int y){
            return root(x) == root(y);
        }
    }
    
    public static void main(String[] args) {
        new Main().m();
    }
    
    private void m() {
        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);
        /*
        try {
            String path = "input.txt";
            out = new PrintWriter(new BufferedWriter(new FileWriter(new File(path))));
        }catch (IOException e){
            e.printStackTrace();
        }
        */
        solve();
        out.flush();
        in.close();
        out.close();
    }
    
    static class FastScanner {
        private Reader input;
        
        public FastScanner() {this(System.in);}
        public FastScanner(InputStream stream) {this.input = new BufferedReader(new InputStreamReader(stream));}
        public void close() {
            try {
                this.input.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        
        public int nextInt() {return (int) nextLong();}
        
        public long nextLong() {
            try {
                int sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                long ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) return ret * sign;
                    ret *= 10;
                    ret += b - '0';
                }
            } catch (IOException e) {
                e.printStackTrace();
                return -1;
            }
        }
        
        public double nextDouble() {
            try {
                double sign = 1;
                int b = input.read();
                while ((b < '0' || '9' < b) && b != '-' && b != '+') {
                    b = input.read();
                }
                if (b == '-') {
                    sign = -1;
                    b = input.read();
                } else if (b == '+') {
                    b = input.read();
                }
                double ret = b - '0';
                while (true) {
                    b = input.read();
                    if (b < '0' || '9' < b) break;
                    ret *= 10;
                    ret += b - '0';
                }
                if (b != '.') return sign * ret;
                double div = 1;
                b = input.read();
                while ('0' <= b && b <= '9') {
                    ret *= 10;
                    ret += b - '0';
                    div *= 10;
                    b = input.read();
                }
                return sign * ret / div;
            } catch (IOException e) {
                e.printStackTrace();
                return Double.NaN;
            }
        }
        
        public char nextChar() {
            try {
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                return (char) b;
            } catch (IOException e) {
                e.printStackTrace();
                return 0;
            }
        }
        
        public String nextStr() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (Character.isWhitespace(b)) {
                    b = input.read();
                }
                while (b != -1 && !Character.isWhitespace(b)) {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public String nextLine() {
            try {
                StringBuilder sb = new StringBuilder();
                int b = input.read();
                while (b != -1 && b != '\n') {
                    sb.append((char) b);
                    b = input.read();
                }
                return sb.toString();
            } catch (IOException e) {
                e.printStackTrace();
                return "";
            }
        }
        
        public int[] nextIntArray(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        
        public int[] nextIntArrayDec(int n) {
            int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt() - 1;
            }
            return res;
        }
        
        public int[] nextIntArray1Index(int n) {
            int[] res = new int[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextInt();
            }
            return res;
        }
        
        public long[] nextLongArray(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong();
            }
            return res;
        }
        
        public long[] nextLongArrayDec(int n) {
            long[] res = new long[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextLong() - 1;
            }
            return res;
        }
        
        public long[] nextLongArray1Index(int n) {
            long[] res = new long[n + 1];
            for (int i = 0; i < n; i++) {
                res[i + 1] = nextLong();
            }
            return res;
        }
        
        public double[] nextDoubleArray(int n) {
            double[] res = new double[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextDouble();
            }
            return res;
        }
    }
}

Measured memory_bytes: 34900