#include<bits/stdc++.h>

using namespace std;

template<typename... T>

void see(T&... args) { ((cin >> args), ...);}

template<typename... T>

void put(T&&... args) { ((cout << args << " "), ...);}

template<typename... T>

void putl(T&&... args) { ((cout << args << " "), ...); cout<<'\n';}

#define int long long

#define pb push_back

#define mp make_pair

#define ff first

#define ss second

#define ll long long

#define ld long double

#define ull unsigned long long

#define print(x) cout << (x)

#define sz size()

#define vc(x) vector<x>

#define nl cout<<'\n'

#define sqof(a) (a)*(a)

#define vi vector<int>

#define vvi vector<vector<int>>

#define pii pair<int,int>

#define vii vector<pii>

#define IOS ios_base:: sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);cin.exceptions(cin.failbit)

#define all(x) (x).begin(), (x).end()

#define setpr(x) cout<<setprecision(x)<<fixed

#define setbits(x) builtin_popcount((x))

#define tostr(x) to_string(x)

#define rep(i,a,b) for(int i=a; i<b; i++)

#define seeArr(arr,n) for(int i=0;i<n;i++){cin>>arr[i];}

#define seeVi(v) for(int i=0;i<v.sz;i++){int x; cin>>x; v.pb(x);}

#define seevi(v) for(int i=0;i<v.sz;i++){cin>>v[i];}

#ifndef ONLINE_JUDGE

#define debug(x) cerr << #x <<" : "; _print(x); cerr << '\n';

#else

#define debug(x)

#endif

void _print(int t) {cerr << t;}

void _print(string t) {cerr << t;}

void _print(char t) {cerr << t;}

void _print(ld t) {cerr << t;}

void _print(double t) {cerr << t;}

void _print(ull t) {cerr << t;}

void _print(bool t) {cerr << t;}

void _print(pair<int, int> t) {cerr << "[ " << t.ff << ", " << t.ss << " ]"; nl;}

template <class T> void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}

const ll infmax = INT_MAX;

const ll infmin = INT_MIN;

const ll N1 = 1e3+2;

const ll N2 = 1e5+2;

const ld ep = 0.0000001;

const ld pi = acos(-1.0);

const ll md = 1000000007;

int gcd(int a, int b){return (!b) ? a : gcd(b, a % b);}

int fact(int n){if(n==1 || n==0){return 1;} return (n*fact(n-1));}

void solve(){

int n; see(n);

vi v(n); seevi(v);

unordered_map<int,int> mp;

rep(i,0,n){

mp[v[i]]++;

}

int ans = 0,two = 0; int d=0;

for(auto x:mp){

d=x.ss;

if(d>=2) two+=(d/2);

}

ans = two/2;

put(ans);

}

signed main() {

#ifndef ONLINE_JUDGE

freopen("error.txt", "w", stderr);

#endif

IOS;

int t=1;

// cin>>t;

while(t--){

solve();

nl;

}

return 0;

}