Problem: Ivan is a novice painter. He has n dyes of different colors. He also knows exactly m pairs of colors which harmonize with each other.

Ivan also enjoy playing chess. He has 5000 rooks. He wants to take k rooks, paint each of them in one of n colors and then place this k rooks on a chessboard of size 10^{9} × 10^{9}.

Let's call the set of rooks on the board connected if from any rook we can get to any other rook in this set moving only through cells with rooks from this set. Assume that rooks can jump over other rooks, in other words a rook can go to any cell which shares vertical and to any cell which shares horizontal.

Ivan wants his arrangement of rooks to have following properties:

  * For any color there is a rook of this color on a board;
  * For any color the set of rooks of this color is connected;
  * For any two different colors a b union of set of rooks of color a and set of rooks of color b is connected if and only if this two colors harmonize with each other.



Please help Ivan find such an arrangement.

Input

The first line of input contains 2 integers n, m (1 ≤ n ≤ 100, 0 ≤ m ≤ min(1000,    (n(n-1))/(2))) — number of colors and number of pairs of colors which harmonize with each other.

In next m lines pairs of colors which harmonize with each other are listed. Colors are numbered from 1 to n. It is guaranteed that no pair occurs twice in this list.

Output

Print n blocks, i-th of them describes rooks of i-th color.

In the first line of block print one number a_{i} (1 ≤ a_{i} ≤ 5000) — number of rooks of color i. In each of next a_{i} lines print two integers x and y (1 ≤ x,    y ≤ 10^{9}) — coordinates of the next rook.

All rooks must be on different cells.

Total number of rooks must not exceed 5000.

It is guaranteed that the solution exists.

Examples

Input

3 2
1 2
2 3


Output

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


Input

3 3
1 2
2 3
3 1


Output

1
1 1
1
1 2
1
1 3


Input

3 1
1 3


Output

1
1 1
1
2 2
1
3 1

Note

Rooks arrangements for all three examples (red is color 1, green is color 2 and blue is color 3).

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Solution (in JAVA):

Solution:
					                                import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.InputMismatchException;
import java.util.TreeSet;
			 
			 
			 
			 
			 
			public class Solution2 implements Runnable
			{
			    static final long MAX = 464897L;
			    static class InputReader
			    {
			        private InputStream stream;
			        private byte[] buf = new byte[1024];
			        private int curChar;
			        private int numChars;
			        private SpaceCharFilter filter;
			        private BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
			 
			        public InputReader(InputStream stream)
			        {
			            this.stream = stream;
			        }
			        
			        public int read()
			        {
			            if (numChars==-1) 
			                throw new InputMismatchException();
			            
			            if (curChar >= numChars)
			            {
			                curChar = 0;
			                try 
			                {
			                    numChars = stream.read(buf);
			                }
			                catch (IOException e)
			                {
			                    throw new InputMismatchException();
			                }
			                
			                if(numChars <= 0)                
			                    return -1;
			            }
			            return buf[curChar++];
			        }
			     
			        public String nextLine()
			        {
			            String str = "";
			            try
			            {
			                str = br.readLine();
			            }
			            catch (IOException e)
			            {
			                e.printStackTrace();
			            }
			            return str;
			        }
			        public int nextInt()
			        {
			            int c = read();
			            
			            while(isSpaceChar(c)) 
			                c = read();
			            
			            int sgn = 1;
			            
			            if (c == '-') 
			            {
			                sgn = -1;
			                c = read();
			            }
			            
			            int res = 0;
			            do 
			            {
			                if(c<'0'||c>'9') 
			                    throw new InputMismatchException();
			                res *= 10;
			                res += c - '0';
			                c = read();
			            }
			            while (!isSpaceChar(c)); 
			            
			            return res * sgn;
			        }
			        
			        public long nextLong() 
			        {
			            int c = read();
			            while (isSpaceChar(c))
			                c = read();
			            int sgn = 1;
			            if (c == '-') 
			            {
			                sgn = -1;
			                c = read();
			            }
			            long res = 0;
			            
			            do 
			            {
			                if (c < '0' || c > '9')
			                    throw new InputMismatchException();
			                res *= 10;
			                res += c - '0';
			                c = read();
			            }
			            while (!isSpaceChar(c));
			                return res * sgn;
			        }
			        
			        public double nextDouble() 
			        {
			            int c = read();
			            while (isSpaceChar(c))
			                c = read();
			            int sgn = 1;
			            if (c == '-') 
			            {
			                sgn = -1;
			                c = read();
			            }
			            double res = 0;
			            while (!isSpaceChar(c) && c != '.') 
			            {
			                if (c == 'e' || c == 'E')
			                    return res * Math.pow(10, nextInt());
			                if (c < '0' || c > '9')
			                    throw new InputMismatchException();
			                res *= 10;
			                res += c - '0';
			                c = read();
			            }
			            if (c == '.') 
			            {
			                c = read();
			                double m = 1;
			                while (!isSpaceChar(c)) 
			                {
			                    if (c == 'e' || c == 'E')
			                        return res * Math.pow(10, nextInt());
			                    if (c < '0' || c > '9')
			                        throw new InputMismatchException();
			                    m /= 10;
			                    res += (c - '0') * m;
			                    c = read();
			                }
			            }
			            return res * sgn;
			        }
			        
			        public String readString() 
			        {
			            int c = read();
			            while (isSpaceChar(c))
			                c = read();
			            StringBuilder res = new StringBuilder();
			            do 
			            {
			                res.appendCodePoint(c);
			                c = read();
			            } 
			            while (!isSpaceChar(c));
			            
			            return res.toString();
			        }
			     
			        public boolean isSpaceChar(int c) 
			        {
			            if (filter != null)
			                return filter.isSpaceChar(c);
			            return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
			        }
			     
			        public String next() 
			        {
			            return readString();
			        }
			        
			        public interface SpaceCharFilter 
			        {
			            public boolean isSpaceChar(int ch);
			        }
			    }
			     
			    public static void main(String args[]) throws Exception
			    {
			        new Thread(null, new Solution2(),"Solution2",1<<26).start();
			    }   
			    static long gcd(long a, long b) 
			    { 
			      if (b == 0) 
			        return a; 
			      return gcd(b, a % b);  
			    } 
			    
			    long MOD = 1000000007;
			    long prime = 29;
			    ArrayList<Integer> adj[];
			    ArrayList<Integer> adj2[];
			    public void run() 
			    {
			    	InputReader sc = new InputReader(System.in);
					PrintWriter w = new PrintWriter(System.out);
					int n = sc.nextInt();
					int m = sc.nextInt();
					adj = new ArrayList[n];
					for(int i = 0;i < n;i++) {
						adj[i] = new ArrayList();
					}
					for(int i = 0;i < m;i++) {
						int a = sc.nextInt()-1;
						int b=  sc.nextInt()-1;
						adj[a].add(b);
					}
					int curr = 0;
					ArrayList<Pair> temp[] = new ArrayList[n];
					for(int i = 0;i < n;i++) {
						temp[i] = new ArrayList();
					}
					for(int i = 0;i < n;i++) {
						if(adj[i].size() == 0) {
							curr++;
							temp[i].add(new Pair(curr,i+1));
							continue;
						}
						for(int j = 0;j < adj[i].size();j++) {
							curr++;
							temp[i].add(new Pair(curr,i+1));
							temp[adj[i].get(j)].add(new Pair(curr,adj[i].get(j)+1));
						}
					}
					for(int i = 0;i < n;i++) {
						w.println(temp[i].size());
						for(int j = 0;j < temp[i].size();j++) {
							w.println(temp[i].get(j).a + " " + temp[i].get(j).b);
						}
					}
		            w.close();
			    }
			    
			    class Pair implements Comparable<Pair>{
			        int a;
			        int b;
			        //int c;
			        Pair(int a,int b){
			            this.b = b;
			            this.a = a;
			        }
			        public boolean equals(Object o) {
			            Pair p = (Pair)o;
			            return this.a == p.a && this.b == this.b;
			        }
			        public int hashCode(){
			            return Long.hashCode(a)*27 + Long.hashCode(b)*31;
			        }
			        public int compareTo(Pair p) {
			        	
			            return Long.compare(p.a - p.b,this.a - this.b);
			        }
			    }
			    
			}