Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

A. SwapSort

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputIn this problem your goal is to sort an array consisting of *n* integers in at most *n* swaps. For the given array find the sequence of swaps that makes the array sorted in the non-descending order. Swaps are performed consecutively, one after another.

Note that in this problem you do not have to minimize the number of swaps — your task is to find any sequence that is no longer than *n*.

Input

The first line of the input contains integer *n* (1 ≤ *n* ≤ 3000) — the number of array elements. The second line contains elements of array: *a*_{0}, *a*_{1}, ..., *a*_{n - 1} ( - 10^{9} ≤ *a*_{i} ≤ 10^{9}), where *a*_{i} is the *i*-th element of the array. The elements are numerated from 0 to *n* - 1 from left to right. Some integers may appear in the array more than once.

Output

In the first line print *k* (0 ≤ *k* ≤ *n*) — the number of swaps. Next *k* lines must contain the descriptions of the *k* swaps, one per line. Each swap should be printed as a pair of integers *i*, *j* (0 ≤ *i*, *j* ≤ *n* - 1), representing the swap of elements *a*_{i} and *a*_{j}. You can print indices in the pairs in any order. The swaps are performed in the order they appear in the output, from the first to the last. It is allowed to print *i* = *j* and swap the same pair of elements multiple times.

If there are multiple answers, print any of them. It is guaranteed that at least one answer exists.

Examples

Input

5

5 2 5 1 4

Output

2

0 3

4 2

Input

6

10 20 20 40 60 60

Output

0

Input

2

101 100

Output

1

0 1

Codeforces (c) Copyright 2010-2019 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Oct/21/2019 01:52:16 (f1).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|