Problem:
Score : 300 points

Problem Statement

We will call a string obtained by arranging the characters contained in a string a in some order, an anagram of a.

For example, greenbin is an anagram of beginner. As seen here, when the same character occurs multiple times, that character must be used that number of times.

Given are N strings s_1, s_2, \ldots, s_N. Each of these strings has a length of 10 and consists of lowercase English characters. Additionally, all of these strings are distinct. Find the number of pairs of integers i, j (1 \leq i < j \leq N) such that s_i is an anagram of s_j.

Constraints

2 \leq N \leq 10^5

s_i is a string of length 10.

Each character in s_i is a lowercase English letter.

s_1, s_2, \ldots, s_N are all distinct.

Input

Input is given from Standard Input in the following format:

N
s_1
s_2
:
s_N

Output

Print the number of pairs of integers i, j (1 \leq i < j \leq N) such that s_i is an anagram of s_j.

Sample Input 1

3
acornistnt
peanutbomb
constraint

Sample Output 1

1

s_1 = acornistnt is an anagram of s_3 = constraint. There are no other pairs i, j such that s_i is an anagram of s_j, so the answer is 1.

Sample Input 2

2
oneplustwo
ninemodsix

Sample Output 2

0

If there is no pair i, j such that s_i is an anagram of s_j, print 0.

Sample Input 3

5
abaaaaaaaa
oneplustwo
aaaaaaaaba
twoplusone
aaaabaaaaa

Sample Output 3

4

Note that the answer may not fit into a 32-bit integer type, though we cannot put such a case here.

Solution in Fortran (gfortran v4.8.4) (judge verdict: Time Limit Exceeded)

module ABC137

  ! <module>s to import
  use, intrinsic :: iso_fortran_env

  ! require all variables to be explicitly declared
  implicit none

  ! accessibility of <subroutine>s and <function>s in this <module>
  public  :: task_C
  private :: fetch_data_string
  private :: isAnagram

  ! constants for this <module>
  integer(INT32), parameter, private :: len_string   = 10_INT32
  integer(INT32), parameter, private :: ichar_a      = ichar("a", kind=INT32)
  integer(INT32), parameter, private :: ichar_z      = ichar("z", kind=INT32)

  ! arrays for this <module>
  character(len=len_string, kind=1), allocatable, private :: given_string(:)
  integer(int8),                     allocatable, private :: data_string (:,:)

  ! contained <subroutine>s and <function>s are below
  contains

  subroutine fetch_data_string (index_target)

    ! arguments for this <subroutine>
    integer(INT32), intent(in) :: index_target

    ! support variables for this <subroutine>
    integer(INT32) :: val_char
    integer(INT32) :: itr

    do itr = 1_INT32, len_string, 1_INT32
      val_char = ichar(given_string(index_target)(itr:itr))
      data_string(val_char, index_target) = data_string(val_char, index_target) + 1_INT32
    end do

    ! STEP.END
    return

  end subroutine fetch_data_string

  pure function isAnagram (index_orign, index_target) result(stat)

    ! arguments for this <function>
    integer(INT32), intent(in) :: index_orign
    integer(INT32), intent(in) :: index_target

    ! return value of this <function>
    logical :: stat

    ! support variables for this <function>
    integer(INT32) :: itr

    ! STEP.01
    ! initialize the return value of this function
    stat = .true.

    ! STEP.02
    ! judge the status of given data
    do itr = ichar_a, ichar_z, 1_INT32
      if ( data_string(itr, index_orign) .ne. data_string(itr, index_target) ) then
        stat = .false.
        exit
      end if
    end do

    ! STEP.END
    return

  end function isAnagram

  subroutine task_C

    ! variables for this <subroutine>
    integer(INT32) :: num_string
    integer(INT64) :: num_anagram

    ! support variables for this <subroutine>
    integer(INT32) :: itr, itr_origin, itr_target

    ! STEP.01
    ! read out the given data

    ! STEP.01.01
    ! read out the number of given strings
    read(unit=INPUT_UNIT, fmt=*) num_string

    ! STEP.01.02
    ! allocate the array to store the given strings
    allocate( given_string(1:num_string) )
    allocate( data_string(ichar_a:ichar_z, 1:num_string) )

    ! STEP.01.03
    ! read out the given strings
    do itr = 1_INT32, num_string, 1_INT32
      read(unit=INPUT_UNIT, fmt=*) given_string(itr)
    end do

    ! STEP.02
    ! calcualte the answer of this task

    ! STEP.02.02
    ! fetch the data of the given string
    data_string(:,:) = 0_INT32

    do itr = 1_INT32, num_string, 1_INT32
      call fetch_data_string(itr)
    end do


    ! STEP.02.02
    ! count up the number of anagram
    num_anagram = 0_INT64

    do itr_origin = 1_INT32,              num_string - 1_INT32, 1_INT32
    do itr_target = itr_origin + 1_INT32, num_string,           1_INT32
      if ( isAnagram (itr_origin, itr_target) ) then
        num_anagram = num_anagram + 1_INT64
      end if
    end do
    end do

    ! STEP.03
    ! output the answer of this task
    write(unit=OUTPUT_UNIT, fmt='(I0)', advance='yes') num_anagram

    ! STEP.04
    ! deallocate the array to store the given strings
    deallocate( given_string )
    deallocate( data_string )

    ! STEP.END
    return

  end subroutine task_C

end module ABC137


program main

  ! <module>s to import
  use, non_intrinsic :: ABC137

  ! require all variables to be explicitly declared
  implicit none

  call task_C

end program main