#include <iostream>
#include <algorithm>
#include <bitset>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <array>
#include <unordered_map>
#include <complex>
#include <deque>
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>
#include <tuple>
#include <cstring>
using namespace std;

#define forr(x,arr) for(auto&& x:arr)
#define _overload3(_1,_2,_3,name,...) name
#define _rep2(i,n) _rep3(i,0,n)
#define _rep3(i,a,b) for(int i=int(a);i<int(b);++i)
#define rep(...) _overload3(__VA_ARGS__,_rep3,_rep2,)(__VA_ARGS__)
#define _rrep2(i,n) _rrep3(i,0,n)
#define _rrep3(i,a,b) for(int i=int(b)-1;i>=int(a);i--)
#define rrep(...) _overload3(__VA_ARGS__,_rrep3,_rrep2,)(__VA_ARGS__)
#define all(x) (x).begin(),(x).end()
#define bit(n) (1LL<<(n))
#define sz(x) ((int)(x).size())
#define TEN(n) ((ll)(1e##n))
#define fst first
#define snd second

string DBG_DLM(int &i){return(i++==0?"":", ");}
#define DBG_B(exp){int i=0;os<<"{";{exp;}os<<"}";return os;}
template<class T>ostream&operator<<(ostream&os,vector<T>v);
template<class T>ostream&operator<<(ostream&os,set<T>v);
template<class T>ostream&operator<<(ostream&os,queue<T>q);
template<class T>ostream&operator<<(ostream&os,priority_queue<T>q);
template<class T,class K>ostream&operator<<(ostream&os,pair<T,K>p);
template<class T,class K>ostream&operator<<(ostream&os,map<T,K>mp);
template<class T,class K>ostream&operator<<(ostream&os,unordered_map<T,K>mp);
template<int I,class TPL>void DBG(ostream&os,TPL t){}
template<int I,class TPL,class H,class...Ts>void DBG(ostream&os,TPL t){os<<(I==0?"":", ")<<get<I>(t);DBG<I+1,TPL,Ts...>(os,t);}
template<class T,class K>void DBG(ostream&os,pair<T,K>p,string delim){os<<"("<<p.first<<delim<<p.second<<")";}
template<class...Ts>ostream&operator<<(ostream&os,tuple<Ts...>t){os<<"(";DBG<0,tuple<Ts...>,Ts...>(os,t);os<<")";return os;}
template<class T,class K>ostream&operator<<(ostream&os,pair<T,K>p){DBG(os,p,", ");return os;}
template<class T>ostream&operator<<(ostream&os,vector<T>v){DBG_B(forr(t,v){os<<DBG_DLM(i)<<t;});}
template<class T>ostream&operator<<(ostream&os,set<T>s){DBG_B(forr(t,s){os<<DBG_DLM(i)<<t;});}
template<class T>ostream&operator<<(ostream&os,queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.front();});}
template<class T>ostream&operator<<(ostream&os,priority_queue<T>q){DBG_B(for(;q.size();q.pop()){os<<DBG_DLM(i)<<q.top();});}
template<class T,class K>ostream&operator<<(ostream&os,map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
template<class T,class K>ostream&operator<<(ostream&os,unordered_map<T,K>m){DBG_B(forr(p,m){os<<DBG_DLM(i);DBG(os,p,"->");});}
#define DBG_OVERLOAD(_1,_2,_3,_4,_5,_6,macro_name,...)macro_name
#define DBG_LINE(){char s[99];sprintf(s,"line:%3d | ",__LINE__);cerr<<s;}
#define DBG_OUTPUT(v){cerr<<(#v)<<"="<<(v);}
#define DBG1(v,...){DBG_OUTPUT(v);}
#define DBG2(v,...){DBG_OUTPUT(v);cerr<<", ";DBG1(__VA_ARGS__);}
#define DBG3(v,...){DBG_OUTPUT(v);cerr<<", ";DBG2(__VA_ARGS__);}
#define DBG4(v,...){DBG_OUTPUT(v);cerr<<", ";DBG3(__VA_ARGS__);}
#define DBG5(v,...){DBG_OUTPUT(v);cerr<<", ";DBG4(__VA_ARGS__);}
#define DBG6(v,...){DBG_OUTPUT(v);cerr<<", ";DBG5(__VA_ARGS__);}
#define DEBUG0(){DBG_LINE();cerr<<endl;}
#ifdef LOCAL
#define out(...){DBG_LINE();DBG_OVERLOAD(__VA_ARGS__,DBG6,DBG5,DBG4,DBG3,DBG2,DBG1)(__VA_ARGS__);cerr<<endl;}
#else
#define out(...)
#endif

using ll=long long;
using pii=pair<int,int>;using pll=pair<ll,ll>;using pil=pair<int,ll>;using pli=pair<ll,int>;
using vs=vector<string>;using vvs=vector<vs>;using vvvs=vector<vvs>;
using vb=vector<bool>;using vvb=vector<vb>;using vvvb=vector<vvb>;
using vi=vector<int>;using vvi=vector<vi>;using vvvi=vector<vvi>;
using vl=vector<ll>;using vvl=vector<vl>;using vvvl=vector<vvl>;
using vd=vector<double>;using vvd=vector<vd>;using vvvd=vector<vvd>;
using vpii=vector<pii>;using vvpii=vector<vpii>;using vvvpii=vector<vvpii>;
template<class A,class B>bool amax(A&a,const B&b){return b>a?a=b,1:0;}
template<class A,class B>bool amin(A&a,const B&b){return b<a?a=b,1:0;}
ll ri(){ll l;cin>>l;return l;} string rs(){string s;cin>>s;return s;}

struct LST {
	const int n;
	const int d;
	vector<vector<uint64_t>> seg;
	int count = 0;

	LST(int _n, bool initial=0) : n(_n ? _n : 1), d(calcd(_n)), seg(d) {
		for (int i=0, m=n>>6; i<d; m>>=6){
			seg[i++].resize(m+1);
		}
		count = initial ? n : 0;

		if (initial) {
			for (int i = 0; i < d; i++, _n=(_n+63)>>6) {
				for (int j = 0; j < _n>>6; j++) {
					seg[i][j] = -1;
				}
				if ((_n&63) != 0) seg[i][_n>>6] |= (1LL<<(_n&63))-1;
			}
		}
	}

	bool empty() const {
		return seg.back()[0] != 0;
	}

	int size() const {
		return count;
	}

	bool get(int pos) const {
		return pos >= 0 && pos < n && (seg[0][pos>>6] & (1LL<<(pos&63)));
	}

	void set(int pos) {
		if (get(pos)) return;
		count++;
		if (pos >= 0 && pos < n) {
			for (int i = 0; i < d; i++) {
				seg[i][pos>>6]|=1LL<<pos;
				pos>>=6;
			}
		}
	}

	void unset(int pos) {
		if (!get(pos)) return;
		count--;
		if (pos >= 0 && pos < n) {
			for (int i=0; i<d && (i==0 || seg[i-1][pos] == 0L); pos>>=6) {
				seg[i][pos>>6] &= ~(1LL<<pos);
				i++;
			}
		}
	}

	int next(int pos) const {
		for (int i = 0; i < d && pos>>6 < (int)seg[i].size(); i++, pos>>=6, pos++){
			int nex = next(seg[i][pos>>6], pos&63);
			if(nex != -1){
				pos = pos>>6<<6|nex;
				while (i > 0) pos = pos<<6|__builtin_ctzll(seg[--i][pos]);
				return pos;
			}
		}
		return -1;
	}

	int prev(int pos) const {
		for (int i = 0; i < d && pos >= 0; i++, pos>>=6, pos--) {
			int pre = prev(seg[i][pos>>6], pos&63);
			if (pre != -1) {
				pos = ((pos>>6)<<6)|pre;
				while (i > 0) {
					--i;
					int clz = seg[i][pos] == 0 ? 64 : __builtin_clzll(seg[i][pos]);
					pos = pos<<6|63-clz;
				}
				return pos;
			}
		}
		return -1;
	}

private:
	static int calcd(int n) {
		int d = 1;
		for (int m = n; m > 1; m >>= 6) {
			d++;
		}
		return d;
	}

	static int next(uint64_t seg, int n) {
		uint64_t h = seg>>n;
		h &= -h;
		if (h == 0) return -1;
		return __builtin_ctzll(h)+n;
	}

	static int prev(uint64_t seg, int n) {
		uint64_t segn = seg<<(63-n);
		if (segn == 0) return -1;
		return n-__builtin_clzll(segn);
	}
};
ostream& operator<<(ostream& os, const LST& lst) {
	vector<int> vec;
	for (int pos = lst.next(0); pos != -1; pos = lst.next(pos+1)) {
		vec.emplace_back(pos);
	}
	os << vec;
	return os;
}

void Main() {
	int n = ri();

	LST lst(1e9+1);

	rep(i, n) {
		int a = ri();
		if (lst.get(a)) lst.unset(a);
		else lst.set(a);
	}
	cout << lst.count << endl;
}

signed main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	Main();
	return 0;
}


Measured memory_bytes: 124288