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.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
       ArrayList<Integer> list=new ArrayList<>();
       int n=sc.nextInt(),m=sc.nextInt(),count=0;
       int a[]=new int[n];
       int b[]=new int[m];
       for(int i=0;i<n;i++){
           for(int j=0;j<m;j++){
               if(a[i]==0||b[j]==0){
                   count++;
                   a[i]++;
                   b[j]++;
                   list.add(i+1);
                   list.add(j+1);
               }
           }
       }
       System.out.println(count);

       int count2=0;
       for(int len:list){
           count2++;
           System.out.print(len+" ");
           if(count2==2){
               System.out.println();
               count2=0;
           }
       }
    }
}