//
// Allow a mixing of SM and SR using the morphing technique
// "graph morph (type B)" in AAAI-99
//
import java.util.*;

public class RandomSMSR { 

    static Random gen;    

    static void shuffle(ArrayList<Integer> v){
	int j,n;
	n = v.size();
	int 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);
	}
    }

    public static void main(String[] args) throws Exception {
	gen                          = new Random();
	int n                        = Integer.parseInt(args[0]); // must be even
	double p                     = Double.parseDouble(args[1]); // (1.0-p) from SM (p=0 <-> SM), p from SR (p=1 <-> SR)
	int m                        = (n*n)/4; // number of edges 
	int mSR                      = (int)(p*m); // number of edges to select from SR
	int mSM                      = m - mSR;  // number of edges to select from SM
	int mIntersection            = 0; // thes size of the intersection between smE and srE
	ArrayList[] adjacent         = new ArrayList[n]; // vertices adjacent to a vertex
	ArrayList<Integer> cliqueE   = new ArrayList<Integer>(); // all possible edges
	ArrayList<Integer> smE       = new ArrayList<Integer>(); // edges in SM
	ArrayList<Integer> srE       = new ArrayList<Integer>(); // edges in SR (with same number of edges in SM)
	ArrayList<Integer> mixE      = new ArrayList<Integer>(); // edges in mixed SM & SR, of size m
	ArrayList<Integer> deleteE   = new ArrayList<Integer>(); // edges to delete
	//
	// create edges in complete bipartite graph smE
	//
	for (int i=0;i<n/2;i++)
	    for (int j=n/2;j<n;j++)
		smE.add(i*n+j);
	//
	// complete clique in srE
	//
	for (int i=0;i<n-1;i++)
	    for (int j=i+1;j<n;j++)
		cliqueE.add(i*n+j);
	//
	// create a random SRI from m shuffled edges in clique
	//
	shuffle(cliqueE);
	for (int i=0;i<m;i++) srE.add(cliqueE.get(i));
	//
	// force intersection of smE and srE in mixE
	//
	for (int e : srE) 
	    if (smE.contains(e)){
		mixE.add(e);
		mIntersection++;
	    }
	for (Integer e : mixE){
	    smE.remove((Integer)e);
	    srE.remove((Integer)e);
	}
	//
	// select mSM and mSR edges and add to mix
	//
	mSR = (int)((m - mIntersection)*p);
	mSM = m - mIntersection - mSR;
	shuffle(smE);
	for (int i=0;i<mSM;i++) mixE.add(smE.get(i));
	shuffle(srE);
	for (int i=0;i<mSR;i++) mixE.add(srE.get(i));
	//
	//Create preference lists
	//
	for (int i=0;i<n;i++) adjacent[i] = new ArrayList<Integer>();	   
	for (Integer e : mixE){
	    int v = e/n;
	    int w = e%n;
	    adjacent[v].add(w);
	    adjacent[w].add(v);
	}
	System.out.println(n);
	for (int i=0;i<n;i++){
	    shuffle(adjacent[i]);
	    for (int j : (ArrayList<Integer>)adjacent[i]) System.out.print((j+1) +" ");
	    System.out.println();
	}
    }
}