Alyona's mother wants to present an array of n non-negative integers to Alyona. The array should be special. 

Alyona is a capricious girl so after she gets the array, she inspects m of its subarrays. Subarray is a set of some subsequent elements of the array. The i-th subarray is described with two integers li and ri, and its elements are a[li], a[li + 1], ..., a[ri].

Alyona is going to find mex for each of the chosen subarrays. Among these m mexes the girl is going to find the smallest. She wants this minimum mex to be as large as possible. 

You are to find an array a of n elements so that the minimum mex among those chosen by Alyona subarrays is as large as possible.

The mex of a set S is a minimum possible non-negative integer that is not in S.

Input

The first line contains two integers n and m (1 ≤ n, m ≤ 105).

The next m lines contain information about the subarrays chosen by Alyona. The i-th of these lines contains two integers li and ri (1 ≤ li ≤ ri ≤ n), that describe the subarray a[li], a[li + 1], ..., a[ri].

Output

In the first line print single integer — the maximum possible minimum mex.

In the second line print n integers — the array a. All the elements in a should be between 0 and 109.

It is guaranteed that there is an optimal answer in which all the elements in a are between 0 and 109.

If there are multiple solutions, print any of them.

Examples

Input

5 3
1 3
2 5
4 5


Output

2
1 0 2 1 0


Input

4 2
1 4
2 4


Output

3
5 2 0 1

Note

The first example: the mex of the subarray (1, 3) is equal to 3, the mex of the subarray (2, 5) is equal to 3, the mex of the subarray (4, 5) is equal to 2 as well, thus the minumal mex among the subarrays chosen by Alyona is equal to 2.
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;

public class TestClass {
	private static InputStream stream;
	private static byte[] buf = new byte[1024];
	private static int curChar;
	private static int numChars;
	private static SpaceCharFilter filter;
	private static PrintWriter pw;
	
	public static class Queue{
		private class node{
			int val;
			node next;
			node(int a){
				val = a;
				next = null;
			}
		}
		node head,tail;
		Queue(){
			head = null;
			tail = null;
		}
		public void EnQueue(int a){
			if(head==null){
				node p = new node(a);
				head = p;
				tail = p;
			}
			else{
				node p = new node(a);
				tail.next = p;
				tail = p;
			}
		}
		public int DeQueue(){
			int a = head.val;
			head = head.next;
			return a;
		}
		public boolean isEmpty(){
			return head==null;
		}
	}
	public static long pow(long x,long y,long m){
		if(y==0)
    		return 1;
    	long k = pow(x,y/2,m);
    	if(y%2==0)
    		return (k*k)%m;
    	else
    		return (((k*k)%m)*x)%m;
    }
	static long Inversex = 0,Inversey = 0;
	public static void InverseModulo(long a,long m){
		if(m==0){
			Inversex = 1;
			Inversey = 0;
		}
		else{
    		InverseModulo(m,a%m);
    		long temp = Inversex;
    		Inversex = Inversey;
    		Inversey = temp+ - (a/m)*Inversey;
    	}
    }
    static long mod1 = 1000000007;
    static long mod2 = 1000000009;
	public static long gcd(long a,long b){
		if(a%b==0)
			return b;
		return gcd(b,a%b);
	}
	public static boolean isPrime(long a){
		if(a==1)
			return false;
		else if(a==2||a==3)
			return true;
		for(long i=2;i<=Math.sqrt(a);i++)
			if(a%i==0)
				return false;
		return true;
	}
	public static double distance(int a,int b,int x,int y){
		return Math.sqrt(((long)(a-x)*(long)(a-x))+((long)(b-y)*(long)(b-y)));
	}
	public static class Pair implements Comparable<Pair> {
		long u;
		long v;
		BigInteger bi;
		public Pair(long u, long v) {
			this.u = u;
			this.v = v;
		}
		public int hashCode() {
			int hu = (int) (u ^ (u >>> 32));
			int hv = (int) (v ^ (v >>> 32));
			return 31 * hu + hv;
		}
		public boolean equals(Object o) {
			Pair other = (Pair) o;
			return u == other.u && v == other.v;
		}
		public int compareTo(Pair other) {
			return Long.compare(u, other.u) != 0 ? Long.compare(u, other.u) : Long.compare(v, other.v);
		}
		public String toString() {
			return "[u=" + u + ", v=" + v + "]";
		}
	}
	public static int seive(int a[],boolean b[],TreeSet<Integer> c){
		int count = 0;
		for(int i=2;i<a.length;i++){
			if(!b[i]){
				for(int j=i*i;j<a.length&&j>0;j=j+i)
					b[j] = true;
				c.add(i);
				a[count++] = i;
			}
		}
		return count;
	}
	public static void MatrixMultiplication(int a[][],int b[][],int c[][]){
		for(int i=0;i<a.length;i++){
			for(int j=0;j<b[0].length;j++){
				c[i][j] = 0;
				for(int k=0;k<b.length;k++)
					c[i][j]=(int)((c[i][j]+((a[i][k]*(long)b[k][j])%mod1))%mod1);
			}
		}
	}
	public static void Equal(int arr[][],int temp[][]){
		for(int i=0;i<arr.length;i++){
			for(int j=0;j<arr.length;j++)
				temp[i][j] = arr[i][j];
		}
	}
	public static class Trie {
		Node head;
		private class Node{
			Node a[] = new Node[2];
			boolean val;
			Node(){
				a[0] = null;
				a[1] = null;
				val = false;
			}
		}
		Trie(){
			head = new Node();
		}
		public void insert(Stack<Integer> s){
			Node temp = head;
			while(!s.isEmpty()){
				int q = s.pop();
				if(temp.a[q]==null)
					temp.a[q] = new Node();
				temp = temp.a[q];
			}
			temp.val = true;
		}
		public Node delete(Stack<Integer> s,Node temp){
			if(s.isEmpty())
				return null;
			int q = s.pop();
			temp.a[q] = delete(s,temp.a[q]);
			if(temp.a[q]==null&&temp.a[q^1]==null)
				return null;
			else
				return temp;
		}
		public void get(Stack<Integer> s,Stack<Integer> p){
			Node temp = head;
			while(!p.isEmpty()){
				int q = p.pop();
				if(temp.a[q]!=null){
					s.push(q);
					temp = temp.a[q];
				}
				else{
					s.push(q^1);
					temp = temp.a[q^1];
				}
			}
		}
	}
	public static void Merge(long a[][],int p,int r){
        if(p<r){
            int q = (p+r)/2;
            Merge(a,p,q);
            Merge(a,q+1,r);
            Merge_Array(a,p,q,r);
        }
    }
	public static void get(long a[][],long b[][],int i,int j){
		for(int k=0;k<a[i].length;k++)
			a[i][k] = b[j][k];
	}
    public static void Merge_Array(long a[][],int p,int q,int r){
        long b[][] = new long[q-p+1][a[0].length];
        long c[][] = new long[r-q][a[0].length];
        for(int i=0;i<b.length;i++){
            get(b,a,i,p+i);
        }
        for(int i=0;i<c.length;i++){
            get(c,a,i,q+i+1);
        }
        int i = 0,j = 0;
        for(int k=p;k<=r;k++){
            if(i==b.length){
                get(a,c,k,j);
                j++;
            }
            else if(j==c.length){
                get(a,b,k,i);
                i++;
            }
            else if(b[i][0]<c[j][0]){
                get(a,b,k,i);
                i++;
            }
            else{
                get(a,c,k,j);
                j++;
            }
        }
    }
    public static void solve(int n){
    	if(n<=1)
    		return ;
    	solve(n/2);
    	MatrixMultiplication(temp2,temp2,result);
		Equal(result,temp2);
    	if(n%2==1){
    		MatrixMultiplication(temp2,a,result);
    		Equal(result,temp2);
    	}
    }
    static int result[][] = new int[4][4];
	static int temp[][] = new int[4][4];
	static int temp2[][] = new int[4][4];
	static int a[][] = new int[4][4];
	static int[][] b = new int[4][1];
	static int [][] c = new int[4][1];
    public static int count(int n){
		a[0][0] = 1 ;
		a[0][1] = 1;
		a[1][0] = 1;
		a[2][1] = 1;
		a[3][0] = 1;
		a[3][1] = 1;
		a[3][3] = 1;
		b[0][0] = 1;
		b[1][0] = 1;
		b[2][0] = 0;
		b[3][0] = 2;
		Equal(a,temp2);
		result[0][0] = 1;
		result[1][1] = 1;
		result[2][2] = 1;
		result[3][3] = 1;
		Equal(result,temp);
		if(n<=0)
			return 0;
		else if(n==1)
			return 1;
		else if(n==2)
			return 2;
		n = n-2;
		solve(n);
		MatrixMultiplication(temp2,b,c);
		return c[3][0];
	}
	private static void soln(){
		int n = nI();
		int m = nI();
		int min = Integer.MAX_VALUE;
		while(m-->0){
			int x = nI();
			int y = nI();
			min = Math.min(y-x+1, min);
		}
		pw.println(min);
		int temp = 0;
		for(int i=0;i<n;i++){
			pw.print(temp+" ");
			temp++;
			if(min==temp)
				temp = 0;
		}
	}
	public static void main(String[] args) {
		InputReader(System.in);
		pw = new PrintWriter(System.out);
		soln();
		pw.close();
	}
	// To Get Input
	// Some Buffer Methods
	public static void InputReader(InputStream stream1) {
		stream = stream1;
	}
	private static boolean isWhitespace(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}
	private static boolean isEndOfLine(int c) {
		return c == '\n' || c == '\r' || c == -1;
	}
	private static 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++];
	}
	private static int nI() {
		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;
	}
	private static long nL() {
		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;
	}
	private static String nextToken() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isSpaceChar(c));
		return res.toString();
	}
	private static String nLi() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while (!isEndOfLine(c));
		return res.toString();
	}
	private static int[] nIA(int n) {
		int[] arr = new int[n];
		for (int i = 0; i < n; i++)
			arr[i] = nI();
		return arr;
	}
	private static long[] nLA(int n) {
		long[] arr = new long[n];
		for (int i = 0; i < n; i++)
			arr[i] = nL();
		return arr;
	}
	private static void pArray(int[] arr) {
		for (int i = 0; i < arr.length; i++)
			pw.print(arr[i] + " ");
		pw.println();
		return;
	}
	private static void pArray(long[] arr) {
		for (int i = 0; i < arr.length; i++)
			pw.print(arr[i] + " ");
		pw.println();
		return;
	}
	private static boolean isSpaceChar(int c) {
		if (filter != null)
			return filter.isSpaceChar(c);
		return isWhitespace(c);
	}
	private interface SpaceCharFilter {
		public boolean isSpaceChar(int ch);
	}
}