CF384B Multitasking

Iahub wants to enhance his multitasking abilities. In order to do this, he wants to sort $ n $ arrays simultaneously, each array consisting of $ m $ integers. Iahub can choose a pair of distinct indices $ i $ and $ j $ $ (1

The first line contains three integers $ n $ $ (1

On the first line of the output print an integer $ p $ , the size of the array ( $ p $ can be at most ). Each of the next $ p $ lines must contain two distinct integers $ i $ and $ j $ $ (1

Consider the first sample. After the first operation, the arrays become $ [1,3,2,5,4] $ and $ [1,2,3,4,5] $ . After the second operation, the arrays become $ [1,2,3,5,4] $ and $ [1,2,3,4,5] $ . After the third operation they become $ [1,2,3,4,5] $ and $ [1,2,3,4,5] $ .