Ciel and Dancing

http://codeforces.com/problemset/problem/322/A

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.

Sample test(s)

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.


Program:
#include<cstdio>
#include<cstring>
#include<iostream>
using namespace std;
int main()
{
    int n,m;
    cin>>n>>m;
    cout<<n+m-1<<endl;
    for(int i=1;i<=m;i++)
    {
        cout<<"1 "<<i<<endl;
    }
    for(int i=2;i<=n;i++)
    {
        cout<<i<<" 1"<<endl;
    }
    return 0;
}