Atcoder Write and Erase

/**
  *  @Author: Pranta Sarker
  *
  */

#include<bits/stdc++.h>

using namespace std;

#define fast ios_base::sync_with_stdio(0)
#define bfast cin.tie(0)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define pfn(x , k) printf(k , x)
#define nl puts("")
#define psb push_back
#define mset(c,v) memset(c , v , sizeof c)
#define loop0(n) for(int i=0; i<n; i++)
#define loop1(n) for(int i=1; i<=n; i++)
#define mpair(x , y) make_pair(x , y)
#define all(x) x.begin(), x.end()
#define pi acos(-1.0)
#define psb push_back
#define clr clear()

typedef unsigned long long ull;
typedef long long LL;
typedef vector<int>vii;
typedef vector<LL>vll;
typedef vector<string>vs;
typedef map<int, int>mpii;
typedef map<string, int>mpsi;
typedef map<char, int>mpci;
typedef map<LL, LL>mpll;

const int mod = 1000007;
const int high = 1e5+2;

mpii mp;

int main()
{
    fast;
    int N , x;
    cin >> N;
    int i=0 , cnt=0;
    for(i=0; i<N; i++)
    {
        cin >> x;
        mp[x]++;
        if(mp[x] == 1) cnt++;
        else cnt--, mp[x] = 0;
    }

    cnt = cnt < 0 ? 0 : cnt;

    outn(cnt);

    return 0;
}