Problem: Bob got a job as a system administrator in X corporation. His first task was to connect n servers with the help of m two-way direct connection so that it becomes possible to transmit data from one server to any other server via these connections. Each direct connection has to link two different servers, each pair of servers should have at most one direct connection. Y corporation, a business rival of X corporation, made Bob an offer that he couldn't refuse: Bob was asked to connect the servers in such a way, that when server with index v fails, the transmission of data between some other two servers becomes impossible, i.e. the system stops being connected. Help Bob connect the servers.

Input

The first input line contains 3 space-separated integer numbers n, m, v (3 ≤ n ≤ 105, 0 ≤ m ≤ 105, 1 ≤ v ≤ n), n — amount of servers, m — amount of direct connections, v — index of the server that fails and leads to the failure of the whole system.

Output

If it is impossible to connect the servers in the required way, output -1. Otherwise output m lines with 2 numbers each — description of all the direct connections in the system. Each direct connection is described by two numbers — indexes of two servers, linked by this direct connection. The servers are numbered from 1. If the answer is not unique, output any.

Examples

Input

5 6 3


Output

1 2
2 3
3 4
4 5
1 3
3 5


Input

6 100 1


Output

-1

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class solver implements Runnable {
    BufferedReader in;
    PrintWriter out;
    StringTokenizer tok = new StringTokenizer("");

    // final boolean OJ = System.getProperty("ONLINE_JUDGE") != null;

    void init() throws FileNotFoundException {

        in = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);

        // try {
        // in = new BufferedReader(new FileReader("input.txt"));
        // out = new PrintWriter("output.txt");
        // } catch (Throwable e) {
        // in = new BufferedReader(new InputStreamReader(System.in));
        // out = new PrintWriter(System.out);
        // }
    }

    String readString() throws IOException {
        while (!tok.hasMoreTokens()) {
            try {
                tok = new StringTokenizer(in.readLine());
            } catch (Exception e) {
                return null;
            }
        }
        return tok.nextToken();
    }

    int readInt() throws IOException {
        return Integer.parseInt(readString());
    }

    long readLong() throws IOException {
        return Long.parseLong(readString());
    }

    double readDouble() throws IOException {
        return Double.parseDouble(readString());
    }

    public static void main(String[] args) {
        new Thread(null, new solver(), "", 128 * (1L << 20)).start();
    }

    public void run() {
        try {
            init();
            long time = System.currentTimeMillis();
            solve();
            System.err.println(System.currentTimeMillis() - time);
            out.close();
        } catch (IOException e) {
            System.err.println(e.getMessage());
            System.exit(-1);
        }
    }

    int gcd(int a, int b) {
        if (b == 0)
            return a;
        return gcd(b, a % b);
    }

    class Pair implements Comparable<Pair> {
        int x;
        int y;

        Pair(int x, int y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public int compareTo(Pair o) {
            // if (x != o.x)
            // return x - o.x;
            return y - o.y;
        }
    }

    int[] iMasWithSort(int n) throws IOException {
        Integer[] a = new Integer[n];
        for (int i = 0; i < n; i++) {
            a[i] = readInt();
        }
        Arrays.sort(a);
        int[] sorted = new int[n];
        for (int i = 0; i < n; i++) {
            sorted[i] = a[i];
        }
        return sorted;
    }

    int[] iMas(int n) throws IOException {
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = readInt();
        }
        return a;
    }

    void solve() throws IOException {
        int n=readInt();
        int m=readInt();
        int v=readInt();
        int root=1;
        if (v==1) root=2;
        ArrayList<Integer> verts=new ArrayList<Integer>();
        for (int i=1;i<=n;i++){
            if (i==v || i==root) continue;
            verts.add(i);
        }
        StringBuilder sb = new StringBuilder();
        sb.append(root+" "+v+"\n");
        sb.append(v+" "+verts.get(0)+"\n");
        m-=2;
        for (int i=0;i<verts.size()-1;i++){
            sb.append(verts.get(i)+" "+verts.get(i+1)+"\n");
            m--;
        }
        if (m<0){
            out.println("-1");
            return;
        }
        for (int i=1;i<verts.size();i++){
            if (m==0) break;
            sb.append(v+" "+verts.get(i)+"\n");
            m--;
        }
        for (int i=0;i<verts.size();i++){
            if (m==0) break;
            for (int j=i+2;j<verts.size();j++){
                if (m==0) break;
                sb.append(verts.get(i)+" "+verts.get(j)+"\n");
                m--;
            }
        }
        if (m>0){
            out.println("-1");
            return;
        }
        out.println(sb.toString());
        
        
        
        
    }
}