#include <bits/stdc++.h>
using namespace std;
long long n, ans = 0, len = 0;
long long a[100010], cnt[10000000];
long long lalala(long long tt) {
  long long ok = 0;
  while (tt) {
    if (tt % 2 == 0)
      tt /= 2;
    else {
      tt /= 2;
      ok++;
    }
  }
  return ok;
}
long long hahaha(long long tt, long long s) {
  long long ok = 1;
  for (long long i = 1; i <= s; i++) {
    ok *= tt;
    tt--;
  }
  for (long long i = s; i >= 1; i--) {
    ok /= i;
  }
  return ok;
}
int main() {
  scanf("%lld", &n);
  for (long long i = 1; i <= n; i++) scanf("%lld", &a[i]);
  for (long long i = 1; i <= n; i++) {
    a[i] = lalala(a[i]);
    cnt[a[i]]++;
    len = max(len, a[i]);
  }
  for (long long i = 1; i <= len; i++) {
    if (cnt[i] >= 2) {
      ans += hahaha(cnt[i], 2);
    }
  }
  printf("%I64d\n", ans);
  return 0;
}
