B. Little Robber Girl's Zoo

time limit per test
2 seconds

memory limit per test
256 megabytes

input
standard input

output
standard output

Little Robber Girl likes to scare animals in her zoo for fun. She decided to arrange the animals in a row in the order of non-decreasing height. However, the animals were so scared that they couldn't stay in the right places.

The robber girl was angry at first, but then she decided to arrange the animals herself. She repeatedly names numbers l and r such
that r - l + 1 is even. After that animals that occupy positions between l and r inclusively
are rearranged as follows: the animal at position l swaps places with the animal at position l + 1,
the animal l + 2 swaps with the animal l + 3,
..., finally, the animal at position r - 1 swaps with the animal r.

Help the robber girl to arrange the animals in the order of non-decreasing height. You should name at most 20 000segments, since otherwise the
robber girl will become bored and will start scaring the animals again.

Input

The first line contains a single integer n (1 ≤ n ≤ 100) —
number of animals in the robber girl's zoo.

The second line contains n space-separated integers a1, a2, ..., an (1 ≤ ai ≤ 109),
where ai is
the height of the animal occupying the i-th place.

Output

Print the sequence of operations that will rearrange the animals by non-decreasing height.

The output should contain several lines, i-th of the lines should contain two space-separated integers li and ri(1 ≤ li < ri ≤ n) —
descriptions of segments the robber girl should name. The segments should be described in the order the operations are performed.

The number of operations should not exceed 20 000.

If the animals are arranged correctly from the start, you are allowed to output nothing.

Examples

input

4
2 1 4 3

output

1 4

input

7
36 28 57 39 66 69 68

output

1 46 7

input

5
1 2 1 2 1

output

2 5
3 4
1 41 4

Note

Note that you don't have to minimize the number of operations. Any solution that performs at most 20 000 operations is allowed.

解题说明：既然在两两交换之后保证数列有序，再加上不需要保证交换次数最少，最简单的方法就是冒泡排序，时间复杂度为n^2。

#include<cstdio>
#include <cstring>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<vector>
#include <map>
using namespace std;

int main()
{
int n,a[105];
int i,j,t;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
scanf("%d",&a[i]);
}
for(i=n;i>=1;i--)
{
for(j=1;j<i;j++)
{
if(a[j]>a[j+1])
{
t=a[j];
a[j]=a[j+1];
a[j+1]=t;
printf("%d %d\n",j,j+1);
}
}
}
return 0;
}