time limit per test

memory limit per test

input

output

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:

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

21 12 1

input

2 2

output

31 11 22 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.

解題思路：n個(gè)boy，m個(gè)girl，若每對(duì)舞伴中至少有一個(gè)之前一次也沒(méi)都跳過(guò)，問(wèn)能夠組成多少對(duì)舞伴，并輸出。

貪心，再加上點(diǎn)數(shù)學(xué)。稍微動(dòng)點(diǎn)數(shù)學(xué)常識(shí)就可以得出，最多可以組成 n+m-1 對(duì)滿足要求的舞伴，然后就是怎么構(gòu)造這么多對(duì)舞伴了。可以這樣想，我們先用1號(hào)boy跟所有的

girl配對(duì)，然后再用剩下的n-1個(gè)boy分別跟最后一個(gè)girl配對(duì)即可。

AC代碼：

#include #include #include #include #include #include #include #include 

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