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.util.*;
import java.io.*;
import java.lang.*;


public class code1
		{
		
			public static int n, m;
		
			public static long[][] cnt;
			public static void main(String[] args)
			{
				InputReader in = new InputReader(System.in);
				PrintWriter pw = new PrintWriter(System.out);
				
				//Code starts..
			
			
				
				
				int n = in.nextInt();
				int m  = in.nextInt();
				int[][] a = new int[m][2];
				pair[] p = new pair[m];
				
				for(int i=0; i<m; i++)
				{
					int l = in.nextInt()-1;
					int r = in.nextInt()-1;
					p[i] = new pair(r-l, i);
					a[i][0] = l;
					a[i][1] = r;
				}
				
				Arrays.sort(p);
				int[] ans = new int[n];
				Arrays.fill(ans, -1);
				int ans2 = -1;
				for(int i=0; i<m; i++)
				{
					int pr = (int)(long)p[i].y;
					int l = a[pr][0];
					int r = a[pr][1];
					if(i==0)
						ans2 = r-l+1;
					
				}
				int k = 0;
				pw.println(ans2);
				for(int i=0; i<n; i++)
				{
					pw.print(k+" ");
					k++;
					if(k==ans2)
						k = 0;
				}
					
					
				//Code ends....
				
				pw.flush();
				pw.close();
				return;
			}
			  
		
			public static int alternateSubarray(int arr[], int n)
			{
				int count = 1;
				int prev = arr[0];
			    int max = 0;
				for (int i = 1; i < n; ++i) {
			 
			        if (arr[i] == prev)
			        {
			        	while (count>0)
			        		count--;
			        		//	System.out.print(count--+" ");
			        		
			        }
			 
			        ++count;
			        max = Math.max(max, count);
			 
			        prev = arr[i];
				}
			 
				return max;
			}
			
			static class InputReader 
			{
				 
				private final InputStream stream;
				private final byte[] buf = new byte[8192];
				private int curChar, snumChars;
				private SpaceCharFilter filter;
		 
				public InputReader(InputStream stream) 
				{
					this.stream = stream;
				}
		 
				public int snext() 
				{
					if (snumChars == -1)
						throw new InputMismatchException();
					if (curChar >= snumChars) 
					{
						curChar = 0;
						try 
						{
							snumChars = stream.read(buf);
						} 
						catch (IOException e) 
						{
							throw new InputMismatchException();
						}
						if (snumChars <= 0)
							return -1;
					}
					return buf[curChar++];
				}
		 
				public int nextInt() 
			    {
					int c = snext();
					while (isSpaceChar(c)) 
					{
						c = snext();
					}
					int sgn = 1;
					if (c == '-')
				    {
						sgn = -1;
						c = snext();
					}
					int res = 0;
					do 
					{
						if (c < '0' || c > '9')
							throw new InputMismatchException();
						res *= 10;
						res += c - '0';
						c = snext();
					} while (!isSpaceChar(c));
					return res * sgn;
				}
		 
				public long nextLong()
			    {
					int c = snext();
					while (isSpaceChar(c)) 
					{
						c = snext();
					}
					int sgn = 1;
					if (c == '-') 
					{
						sgn = -1;
						c = snext();
					}
					long res = 0;
					do 
					{
						if (c < '0' || c > '9')
							throw new InputMismatchException();
						res *= 10;
						res += c - '0';
						c = snext();
					} while (!isSpaceChar(c));
					return res * sgn;
				}
		 
				public int[] nextIntArray(int n) 
				{
					int a[] = new int[n];
					for (int i = 0; i < n; i++) 
					{
						a[i] = nextInt();
					}
					return a;
				}
		 
				public String readString()
			    {
					int c = snext();
					while (isSpaceChar(c)) 
					{
						c = snext();
					}
					StringBuilder res = new StringBuilder();
					do 
					{
						res.appendCodePoint(c);
						c = snext();
					} while (!isSpaceChar(c));
					return res.toString();
				}
		 
				public String nextLine() 
				{
					int c = snext();
					while (isSpaceChar(c))
						c = snext();
					StringBuilder res = new StringBuilder();
					do 
					{
						res.appendCodePoint(c);
						c = snext();
					} while (!isEndOfLine(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;
				}
		 
				private boolean isEndOfLine(int c) 
				{
					return c == '\n' || c == '\r' || c == -1;
				}
		 
				public interface SpaceCharFilter
			    {
					public boolean isSpaceChar(int ch);
				}
			}
			public static long c = 0;
			
			public static long mod = 1000000007;
			public static int d;
			public static int p;
			public static int q;
			public static boolean flag;
			public static long INF= Long.MAX_VALUE;
			
			public static long fun(int[] a, int[] b, int m,int n) {
				long result =0;
				for(int i=0; i<m; i++)
					for(int j=0; j<m; j++)
					{
						long[] fib  = new long[Math.max(2, n+2)];
						fib[1] = a[i];
						fib[2] = b[j];
						for(int k=3; k<=n; k++)
							fib[k] = (fib[k-1]%mod + fib[k-2]%mod)%mod;
						result = (result%mod + fib[n]%mod)%mod;
					}
				
				return result;
				
			}
			
			
			public static double slope(pair p1, pair p2)
			{
				double m = INF;
				if((p1.x - p2.x)!=0)
				m =  (p1.y - p2.y)/(p1.x - p2.x); 
				
				
				return Math.abs(m);
				
			}
			
			
			public static int count(String[] s, int f)
			{
				int count = 0;
				int n = s[0].length();
				
				if(f==1)
				{
				for(int i = 0; i<n; i++)
				{
					for(int j=0; j<n; j++)
					{
						if(i%2==0)
						{
							if(j%2==0 && s[i].charAt(j)=='0')
								count++;
							if(j%2==1 && s[i].charAt(j)=='1')
								count++;
						}
						if(i%2==1)
						{
							if(j%2==1 && s[i].charAt(j)=='0')
								count++;
							if(j%2==0 && s[i].charAt(j)=='1')
								count++;
						}
						
					}
				}
				}
				else
				{
				
				 count = 0;
				
				for(int i = 0; i<n; i++)
				{
					for(int j=0; j<n; j++)
					{
						if(i%2==1)
						{
							if(j%2==0 && s[i].charAt(j)=='0')
								count++;
							if(j%2==1 && s[i].charAt(j)=='1')
								count++;
						}
						if(i%2==0)
						{
							if(j%2==1 && s[i].charAt(j)=='0')
								count++;
							if(j%2==0 && s[i].charAt(j)=='1')
								count++;
						}
						
					}
				}
	 
				}	
					
			
				return count;
				
				
				
			}
					
			public static  int gcd(int p2, int p22)
			{
			    if (p2 == 0)
			        return (int) p22;
			    return gcd(p22%p2, p2);
			}
			
				
		
			
			
			public static int findGCD(int arr[], int n)
			{
			    int result = arr[0];
			    for (int i=1; i<n; i++)
			        result = gcd(arr[i], result);
			 
			    return result;
			}
			
		
	 
			public static void nextGreater(long[] a, int[] ans)
			{
				
				Stack<Integer> stk = new Stack<>();
				stk.push(0);
				
				
				for(int i=1; i<a.length; i++)
				{
					
					if(!stk.isEmpty())
					{
					int s = stk.pop();
					while(a[s]<a[i])
					{
						ans[s] = i;
						if(!stk.isEmpty())
							s = stk.pop();
						else
							break;
					}
					if(a[s]>=a[i])
						stk.push(s);
					}
					
					stk.push(i);
					
				}
				return;
				
			}
			
			public static void nextGreaterRev(long[] a, int[] ans)
			{
				
				int n = a.length;
				int[] pans = new int[n];
				Arrays.fill(pans, -1);
				long[] arev = new long[n];
				for(int i=0; i<n; i++)
					arev[i] = a[n-1-i];
				
				Stack<Integer> stk = new Stack<>();
				stk.push(0);
				
				
				for(int i=1; i<n; i++)
				{
					
					if(!stk.isEmpty())
					{
					int s = stk.pop();
					while(arev[s]<arev[i])
					{
						pans[s] = n - i-1;
						if(!stk.isEmpty())
							s = stk.pop();
						else
							break;
					}
					if(arev[s]>=arev[i])
						stk.push(s);
					}
					
					stk.push(i);
					
				}
				
				//for(int i=0; i<n; i++)
					//System.out.print(pans[i]+" ");
				
				for(int i=0; i<n; i++)
					ans[i] = pans[n-i-1];
				
				
				
				return;
				
			}
			
			
			public static void nextSmaller(long[] a, int[] ans)
			{
				
				Stack<Integer> stk = new Stack<>();
				stk.push(0);
				
				
				for(int i=1; i<a.length; i++)
				{
					
					if(!stk.isEmpty())
					{
					int s = stk.pop();
					while(a[s]>a[i])
					{
						ans[s] = i;
						if(!stk.isEmpty())
							s = stk.pop();
						else
							break;
					}
					if(a[s]<=a[i])
						stk.push(s);
					}
					
					stk.push(i);
					
				}
				return;
				
			}
			

			public static void print(int[] a)
			{
				PrintWriter pw = new PrintWriter(System.out);
				for(int i=0; i<a.length; i++)
					pw.print(a[i]+" ");
				
				pw.println();
				pw.flush();
				pw.close();
				
			}
			
			public static void print(long[] a)
			{
				PrintWriter pw = new PrintWriter(System.out);
				for(int i=0; i<a.length; i++)
					pw.print(a[i]+" ");
				
				pw.println();
				pw.flush();
				pw.close();
				
			}
			
			
		    public static long lcm(int[] numbers) {
		        long lcm = 1;
		        int divisor = 2;
		        while (true) {
		            int cnt = 0;
		            boolean divisible = false;
		            for (int i = 0; i < numbers.length; i++) {
		                if (numbers[i] == 0) {
		                    return 0;
		                } else if (numbers[i] < 0) {
		                    numbers[i] = numbers[i] * (-1);
		                }
		                if (numbers[i] == 1) {
		                    cnt++;
		                }
		                if (numbers[i] % divisor == 0) {
		                    divisible = true;
		                    numbers[i] = numbers[i] / divisor;
		                }
		            }
		            if (divisible) {
		                lcm = lcm * divisor;
		            } else {
		                divisor++;
		            }
		            if (cnt == numbers.length) {
		                return lcm;
		            }
		        }
		    }
			public static long fact(long n) {
				
				long factorial = 1;
				 for(int i = 1; i <= n; i++)
			        {
			            factorial *= i;
			        }
				 return factorial;
			}
			
	public static void factSieve(int[] a, int n) {
				
				
				for(int i=2; i<=n; i+=2)
					a[i] = 2;
				
				
				for(int i=3; i<=n; i+=2)
				{
					if(a[i]==0)
					{
						a[i] = i;
						
						for(int j=i; j*i<=n; j++)
						{
							a[i*j] = i;	
						}
					}
				}
				
				int k = 1000;
				while(k!=1)
				{
					System.out.print(a[k]+" ");
					k /= a[k];
					
				}
			}
		
			
			public static int lowerLimit(int[] a, int n) {
				int ans = 0;
				
				int ll = 0;
				int rl = a.length-1;
			//	System.out.println(a[rl]+" "+n);
				if(a[0]>n)
					return 0;
				if(a[0]==n)
					return 1;
				else if(a[rl]<=n)
					return rl+1;
			
				while(ll<=rl)
				{
					
					int mid = (ll+rl)/2;
					if(a[mid]==n)
					{
						ans = mid + 1;
						break;
					}
					
					else if(a[mid]>n)
					{
						rl = mid-1;
						
					}
					else
					{
						ans = mid+1;
						ll = mid+1;
					}
				}
				
				return ans; 
			}
			
			
			public static long choose(long total, long choose){
			    if(total < choose)
			        return 0;
			    if(choose == 0 || choose == total)
			        return 1;
			    return (choose(total-1,choose-1)+choose(total-1,choose))%mod;
			}
			
			public static int[] suffle(int[] a,Random gen)
			{
				int n = a.length;
				for(int i=0;i<n;i++)
				{
					int ind = gen.nextInt(n-i)+i;
					int temp = a[ind];
					a[ind] = a[i];
					a[i] = temp;
				}
				return a;
			}
			
			public static long[] sort(long[] a)
			{
				Random gen = new Random();
				int n = a.length;
				for(int i=0;i<n;i++)
				{
					int ind = gen.nextInt(n-i)+i;
					long temp = a[ind];
					a[ind] = a[i];
					a[i] = temp;
				}
				
				Arrays.sort(a);
				return a;
			}
			
			public static pair[] sort(pair[] a)
			{
				Random gen = new Random();
				int n = a.length;
				for(int i=0;i<n;i++)
				{
					int ind = gen.nextInt(n-i)+i;
					pair temp = a[ind];
					a[ind] = a[i];
					a[i] = temp;
				}
				
				Arrays.sort(a);
				return a;
			}
			
			
			public static int[] sort(int[] a)
			{
				Random gen = new Random();
				int n = a.length;
				for(int i=0;i<n;i++)
				{
					int ind = gen.nextInt(n-i)+i;
					int temp = a[ind];
					a[ind] = a[i];
					a[i] = temp;
				}
				
				Arrays.sort(a);
				return a;
			}
			
			public static int floorSearch(int arr[], int low, int high, int x)
			{
			    if (low > high)
			        return -1;
			 
			    if (x > arr[high])
			        return high;
			    int mid = (low+high)/2;
			 
			 
			    if (mid > 0 && arr[mid-1] < x && x < arr[mid])
			        return mid-1;
			 
			    if (x < arr[mid])
			        return floorSearch(arr, low, mid-1, x);
			 
			    return floorSearch(arr, mid+1, high, x);
			}
			
			
			public static void swap(int a, int b){
				int temp = a;
				a = b;
				b = temp;
			}
			public static ArrayList<Integer> primeFactorization(int n)
			{
				ArrayList<Integer> a =new ArrayList<Integer>();
				for(int i=2;i*i<=n;i++)
				{
					while(n%i==0)
					{
						a.add(i);
						n/=i;
					}
				}
				if(n!=1)
					a.add(n);
				return a;
			}
			
			
			public static void sieve(boolean[] isPrime,int n)
			{
				for(int i=1;i<n;i++)
					isPrime[i] = true;
				
				isPrime[0] = false;
				isPrime[1] = false;
				
				for(int i=2;i*i<n;i++)
				{
					if(isPrime[i] == true)
					{
						for(int j=(2*i);j<n;j+=i)
							isPrime[j] = false;
					}
				}
			}
			
			public static int lowerbound(ArrayList<Long> net, long c2) {
				int i=Collections.binarySearch(net, c2);
				if(i<0)
					i = -(i+2);
				return i;
				
				
			}
		
			public static int lowerboundArray(long[] psum, long c2) {
				int i=Arrays.binarySearch(psum, c2);
				if(i<0)
					i = -(i+2);
				return i;
				
				
			}
			
			public static int lowerboundArray(int[] psum, int c2) {
				int i=Arrays.binarySearch(psum, c2);
				if(i<0)
					i = -(i+2);
				return i;
				
				
			}
			
			
			public static int uperboundArray(long[] psum, long c2) {
				int i=Arrays.binarySearch(psum, c2);
				if(i<0)
					i = -(i+1);
				return i;
				
				
			}
			
			
			public static int uperbound(ArrayList<Long> net, long c2) {
				int i=Collections.binarySearch(net, c2);
				if(i<0)
					i = -(i+1);
				return i;
				
				
			}
			
			
			public static int GCD(int a,int b)
			{
				if(b==0)
					return a;
				else
					return GCD(b,a%b);
			}
			
			public static long GCD(long a,long b)
			{
				if(b==0)
					return a;
				else
					return GCD(b,a%b);
			}
			
			public static void extendedEuclid(int A,int B)
			{
				if(B==0)
				{
					d = A;
					p = 1 ;
					q = 0;
				}
				else
				{
					extendedEuclid(B, A%B);
					int temp = p;
					p = q;
					q = temp - (A/B)*q;
				}
			}
			
			public static long LCM(long a,long b)
			{
				return (a*b)/GCD(a,b);
			}
			
			public static int LCM(int a,int b)
			{
				return (a*b)/GCD(a,b);
			}
			
			public static int binaryExponentiation(int x,int n)
			{
			    int result=1;
			    while(n>0)
			    {
			        if(n % 2 ==1)
			            result=result * x;
			        x=x*x;
			        n=n/2;
			    }
			    return result;
			}
			
			
			public static int[] countDer(int n)
		    {
		        int der[] = new int[n + 1];
		     
		        der[0] = 1;
		        der[1] = 0;
		        der[2] = 1;
		     
		        for (int i = 3; i <= n; ++i)
		            der[i] = (i - 1) * (der[i - 1] + der[i - 2]);
		     
		        // Return result for n
		        return der;
		    }
			
			
			 static long binomialCoeff(int n, int k)
			    {
			    long C[][] = new long[n+1][k+1];
			    int i, j;
			     
			        // Calculate  value of Binomial Coefficient in bottom up manner
			    for (i = 0; i <= n; i++)
			    {
			        for (j = 0; j <= Math.min(i, k); j++)
			        {
			            // Base Cases
			            if (j == 0 || j == i)
			                C[i][j] = 1;
			      
			            // Calculate value using previosly stored values
			            else
			                C[i][j] = C[i-1][j-1] + C[i-1][j];
			          }
			     }
			      
			    return C[n][k];
			    }
			
			public static long binaryExponentiation(long x,long n)
			{
			    long result=1;
			    while(n>0)
			    {
			        if(n % 2 ==1)
			            result=result * x;
			        x=(x%mod * x%mod)%mod;
			        n=n/2;
			    }
			    return result;
			}
			
			public static int modularExponentiation(int x,int n,int M)
			{
			    int result=1;
			    while(n>0)
			    {
			        if(n % 2 ==1)
			            result=(result * x)%M;
			        x=(x%M*x%M)%M;
			        n=n/2;
			    }
			    return result;
			}
			
			public static long modularExponentiation(long x,long n,long M)
			{
			    long result=1;
			    while(n>0)
			    {
			        if(n % 2 ==1)
			            result=(result %M* x%M)%M;
			        x=(x*x)%M;
			        n=n/2;
			    }
			    return result;
			}
			
			public static int modInverse(int A,int M)
			{
			    return modularExponentiation(A,M-2,M);
			}
			
			public static long modInverse(long A,long M)
			{
			    return modularExponentiation(A,M-2,M);
			}
			
			
			public static boolean checkYear(int year)
		    {
				if (year % 400 == 0)
		            return true;
		     
		        if (year % 100 == 0)
		            return false;
		     
		        if (year % 4 == 0)
		            return true;
		        return false;
		    }
			
			public static boolean isPrime(int n)
			{
			    
			    if (n <= 1)  return false;
			    if (n <= 3)  return true;
			    
			    if (n%2 == 0 || n%3 == 0) 
			    	return false;
			 
			    for (int i=5; i*i<=n; i=i+6)
			    {
			        if (n%i == 0 || n%(i+2) == 0)
			           return false;
			    }
			    
			    return true;
			}
			
			static class pair implements Comparable<pair>
	
			{
				Long x, y;
	
				pair(long x, long y) {
					this.x = x;
					this.y = y;
				}
	
				public int compareTo(pair o) {
					int result = x.compareTo(o.x);
					if (result == 0)
						result = y.compareTo(o.y);
	
					return result;
				}
	
				public String toString() {
					return x + " " + y;
				}
	
				public boolean equals(Object o) {
					if (o instanceof pair) {
						pair p = (pair) o;
						if(p.x-x==0 && p.y-y==0)
							return true;
						else
						return false;
					}
					return false;
				}
	
				public int hashCode() {
					return new Long(x).hashCode() * 31 + new Long(y).hashCode();
				}
	
			}
			
			
			static class triplet implements Comparable<triplet>
			{
				Integer x,y;
				Long z;
				triplet(Integer l,Integer m,long z)
				{
					this.x = l;
					this.y = m;
					this.z = z;
				}
				
				public  int compareTo(triplet o)
				{
					int result = x.compareTo(o.x);
					if(result==0)
						result =  y.compareTo(o.y);
					if(result==0)
						result = z.compareTo(o.z);
	 
					return result;
				}
				
				public boolean equlas(Object o)
				{
					if(o instanceof triplet)
					{
						triplet p = (triplet)o;
						return x==p.x && y==p.y && z==p.z;
					}
					return false;
				}
				
				public String toString()
				{
					return x+" "+y+" "+z;
				}
				public int hashCode()
				{
					return new Long(x).hashCode()*31 + new Long(y).hashCode() + new Long(z).hashCode(); 
				}
			}
			
			static class spair implements Comparable<spair>
	
			{
				String x;
				Integer y;
	
				spair(String x, int y) {
					this.x = x;
					this.y = y;
				}
	
				public int compareTo(spair o) {
					
					String s1 = x + o.x;
					String s2 = o.x + x;
					long p1 = cnt[y][0] + cnt[o.y][0];
					long p2 = p1;
					
					p1 += cnt[y][1] * cnt[o.y][2];
					p2 += cnt[o.y][1] * cnt[y][2];
					
					if(p1==p2)
							return 0;
					if(p1>p2)
						return -1;
					
					return 1;
					
					
					
					
				}
	
				public String toString() {
					return x + " " + y;
				}
	
				/*public boolean equals(Object o) {
					if (o instanceof pair) {
						pair p = (pair) o;
						return p.x == x && p.y == y;
					}
					return false;
				}
	
				public int hashCode() {
					return new Long(x).hashCode() * 31 + new Long(y).hashCode();
				}
				
	
			}
	
			
			
			
		
			/*static class node implements Comparable<node>
	 
			{
				Integer x, y, z;
				node(int x,int y, int z)
				{
					this.x=x;
					this.y=y;
					this.z=z;
				}
				
				public int compareTo(pair o) {
					int result = x.compareTo(o.x);
					if(result==0)
						result = y.compareTo(o.y);
					if(result==0)
						result = z.compareTo(z); 
					return result;
				}
	 
				@Override
				public int compareTo(node o) {
					// TODO Auto-generated method stub
					return 0;
				}  
			}
			*/
		}
		}
		
			