#include <bits/stdc++.h>

using namespace std;
typedef long long int ll;
typedef pair<ll,ll> pll;
typedef vector<ll> vll;

#define repi(i,a,b) for(ll i=a;i<b;i++)
#define rep(i,a) repi(i,0,a)
#define rrep(i,a) for(ll i=a-1;i>=0;i--)
#define MOD 1000000007

//debug
#define debug(arr) cerr<<#arr<<"(l"<<__LINE__<<") : ";for(auto x:arr)cerr<<x<<" ";cerr<<endl;

int main(){
  ll N;
  cin >> N;
  ll A[N];
  rep(i, N) cin >> A[i];

  sort(A, A+N);
  ll ans = 0;
  ll prev = A[0];
  ll cnt = 1;
  repi(i, 1, N) {
    if (A[i] == prev) {
      cnt++;
      if (cnt % 2 == 0) ans++;
    }
    else {
      cnt = 1;
    }
    prev = A[i];
  }

  cout << ans << endl;
  return 0;
}