Dima got into number sequences. Now he's got sequence *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub>, consisting of *n* positive integers. Also, Dima has got a function *f*(*x*), which can be defined with the following recurrence:
 -  *f*(0) = 0; -  *f*(2·*x*) = *f*(*x*); -  *f*(2·*x* + 1) = *f*(*x*) + 1. 
Dima wonders, how many pairs of indexes (*i*, *j*) (1 ≤ *i* &lt; *j* ≤ *n*) are there, such that *f*(*a*<sub class="lower-index">*i*</sub>) = *f*(*a*<sub class="lower-index">*j*</sub>). Help him, count the number of such pairs.
The first line contains integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">5</sup>). The second line contains *n* positive integers *a*<sub class="lower-index">1</sub>, *a*<sub class="lower-index">2</sub>, ..., *a*<sub class="lower-index">*n*</sub> (1 ≤ *a*<sub class="lower-index">*i*</sub> ≤ 10<sup class="upper-index">9</sup>).

The numbers in the lines are separated by single spaces.
# https://codeforces.com/problemset/problem/272/B

def calculate(no):
    if no & (no-1) == 0:
        return 1
    no //= 2
    if no & 1 == 0:
        return calculate(no)
    else:
        return 1 + calculate(no)

if __name__ == "__main__":
    n = int(input())
    nos = input().split(" ")
    intarr = []
    for no in nos:
        intarr.append(int(no))

    count = dict()
    for i in intarr:
        e = calculate(i)
        if e in count:
            count[e] += 1
        else:
            count[e] = 1

    answer = 0
    for val in count.values():
        if val > 1:
            answer = val * (val-1) // 2

    print(answer)

