unique

#include <bits/stdc++.h>
using namespace std;
bitset<200001> a,b;

int main()
{
    int x, cnt=0;
    while(cin>>x)
    {
        if(a[x]==0)
            ++cnt,a[x]=1;
        else
        {
            if(b[x]==0)
                --cnt;
            b[x]=1;
        }
    }
    cout<<cnt;
    return 0;
}