Igor has a huge collection of folk hits on his computer, containing
songs numbered
to
. The collection is so big that it is not possible
to display all songs at once on his display. Because of this, while a
song is playing, only
consecutive songs from the collection are
displayed on the screen. Of course, the
consecutive songs necessarily
include the song currently playing.
When a song first appears on the display, the software needs to access its file on disk and read metadata like artist and song name. This metadata is stored in the computer's memory so that, if the song reappears on display, the file doesn't need to be opened again.
Your program will be given the songs Igor wants to listen to, in the order in which he wants to do it. For each song, determine the interval of songs which will be displayed while it is playing, so that the total number of files that need to be accessed on disk is the smallest possible.
Note: The solution may not be unique.
Input Specification
The first line contains two integers and
,
the number of songs in the collection and the
number of songs displayed.
The second line contains the integer
,
the number of songs Igor will listen to.
The next lines contain the indices of the songs Igor will listen to.
All numbers will be between
and
and no song will appear more than
once.
Output Specification
Output should consist of lines.
On the first line output the smallest possible number of files to access while playing Igor's playlist.
After this, for each song , in order in which they are given, output a
pair of integers
and
, meaning that while song
is playing, songs
through
(inclusive) are displayed on screen.
and
must satisfy the
conditions
, and
.
Scoring
An output which is not completely correct, but the first line (the least
number of files to access) is correct, will score points for that
test case.
Sample Input 1
10 3
5
4
5
8
7
6
Sample Output 1
5
4 6
4 6
6 8
6 8
6 8
Sample Input 2
15 4
6
6
14
11
3
8
5
Sample Output 2
10
3 6
11 14
11 14
3 6
5 8
3 6
Sample Input 3
1000 301
3
300
500
700
Sample Output 3
401
300 600
350 650
400 700
Comments