import java.util.*;

public class RandomRoommate { 

    static Random gen;    

    static void shuffle(ArrayList<Object> v){
	int j,n;
	n = v.size();
	Object temp;
	for (int i=n-1;i>0;i--){
	    j = gen.nextInt(i+1);
	    temp = v.get(i);
	    v.set(i,v.get(j));
	    v.set(j,temp);
	}
    }

    static Edge randomSelect(ArrayList<Edge> v){
	if (v.isEmpty()) return null;
	return v.get(gen.nextInt(v.size()));
    }

    public static void main(String[] args) throws Exception {
	gen               = new Random();
	int n             = Integer.parseInt(args[0]);
	double p          = 1.0; 
	double pForced    = 0.0;
	ArrayList[] V     = new ArrayList[n];
	ArrayList<Edge> E = new ArrayList<Edge>();
	ArrayList<Integer> agent = new ArrayList<Integer>(n);
	for (int i=0;i<n;i++) V[i] = new ArrayList<Integer>();	    
	if (args.length >= 2) p = Double.parseDouble(args[1]);
	System.out.println(n);
	for (int i=0;i<n-1;i++)
	    for (int j=i+1;j<n;j++)
		if (p >= gen.nextDouble()){
		    V[i].add(j);
		    V[j].add(i);
		    E.add(new Edge(i,j));
		}
	for (int i=0;i<n;i++){
	    shuffle(V[i]);
	    for (int j : (ArrayList<Integer>)V[i]) System.out.print((j+1) +" ");
	    System.out.println();
	}
	if (args.length >= 3) pForced = Double.parseDouble(args[2]);
	for (int i=0;i<n;i++) agent.add(i);
	for (int i=0;i<n;i++){
	    Edge e = randomSelect(E);
	    if (e != null && pForced >= gen.nextDouble()){
		System.out.println("forced "+ (e.v+1) +" "+ (e.w+1));
		ArrayList<Edge> deletions = new ArrayList<Edge>();
		for (Edge e2 : E) if (e.adjacent(e2)) deletions.add(e2);
		for (Edge e2 : deletions) E.remove(e2);
	    }
	}
    }
}