Qustion91

#include<bits/stdc++.h>
using namespace std;

#define      ll        long long
#define      yes       cout<<"YES"<<endl 
#define      no        cout<<"NO"<<endl 
#define      vp        vector<pair<ll, ll>> 
#define      vl        vector<ll>
#define      vvl       vector<vector<ll>>
#define      vvlin     for(int i=0;i<vec.size();i++){ for(int j=0;j<vec[i].size();j++){ cin>>vec[i][j];}}
#define      vvlout    for(int i=0;i<vec.size();i++){ for(int j=0;j<vec[i].size();j++){ cout<<vec[i][j]<<" ";}}
#define      arrin     ll a[n]; for(int i=0;i<n;i++){cin>>a[i];}
#define      fin       for(int i=0;i<n;i++)
#define      fjn       for(int j=0;j<n;j++)
#define      fkn       for(int k=0;k<n;k++)
#define      arrout    for(int i=0;i<n;i++){cout<<a[i]<<" ";}
const int M=1e9+7;

int main(){
     ios_base::sync_with_stdio(false);
     cin.tie(NULL);

    ll n;cin>>n;
    ll a[n];
    fin{
        cin>>a[i];
    }
    unordered_map<ll,ll>hash;
    fin{
        hash[a[i]]++;
    }
    ll c=0;
    for(auto it:hash){
           c+=(it.second/2);
    }
    cout<<c<<"\n";
    return 0;
}