Fox Ciel and her friends are in a dancing room. There are n boys and m girls here, and they never danced before. There will be some songs, during each song, there must be exactly one boy and one girl are dancing. Besides, there is a special rule:

  * either the boy in the dancing pair must dance for the first time (so, he didn't dance with anyone before); 
  * or the girl in the dancing pair must dance for the first time. 



Help Fox Ciel to make a schedule that they can dance as many songs as possible.

Input

The first line contains two integers n and m (1 ≤ n, m ≤ 100) — the number of boys and girls in the dancing room.

Output

In the first line print k — the number of songs during which they can dance. Then in the following k lines, print the indexes of boys and girls dancing during songs chronologically. You can assume that the boys are indexed from 1 to n, and the girls are indexed from 1 to m.

Examples

Input

2 1


Output

2
1 1
2 1


Input

2 2


Output

3
1 1
1 2
2 2

Note

In test case 1, there are 2 boys and 1 girl. We can have 2 dances: the 1st boy and 1st girl (during the first song), the 2nd boy and 1st girl (during the second song).

And in test case 2, we have 2 boys with 2 girls, the answer is 3.


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

public class Codechef
{      
    
    
    public static void main (String[] args) throws java.lang.Exception
    {
        

      Scanner sc = new Scanner(System.in);
          int n=sc.nextInt();
          int m=sc.nextInt();
         int arr[]=new int[1000000];
         int brr[]=new int[1000000];
         int k=0;
         int count=0;
         for(int i=1;i<=n;i++){
          if(i==1){
             for(int j=1;j<=m;j++){
              arr[j]=i;
              brr[j]=j;
              count++;

          }
            k=m;
    
          }else{
            arr[k+1]=i;
            brr[k+1]=brr[m];
            k++;
              count++;

          }

         

         
         }
         System.out.println(count);
         for(int i=0;i<n+m;i++){
                if(arr[i]!=0 && brr[i]!=0){
                  System.out.println(arr[i]+" "+brr[i]);
                }
         }
        
  

 
































}
           

}

