#include "bits/stdc++.h"
using namespace std;
 
typedef long long ll;
typedef vector<int> vi;

#define fast ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define FOR(i,a,b) for(int i = a; i<=b; ++i)
#define NFOR(i,a,b) for(int i = a; i>=b; --i)
#define FILL(A,value) memset(A,value,sizeof(A))
#define pb push_back
#define mp make_pair
#define sz(a) (int)(a.size())
 
const ll INF = 1e18;
const int mod = 1e9+7;
const int N = 1e5+10;
 
ll factorial(int n){
  return (n == 1 || n == 0) ? 1 : (factorial(n - 1) * n);
}
ll power(ll x,  ll y ){
    ll res = 1;   
    while (y > 0){        
        if (y & 1)
            res = res*x%mod;
        y = y/2;
        x = x*x%mod; 
    }
    return res;
} 

int main(){
	fast ; 
	ll  n ;
	cin >>  n ;
	vi v(n);
	//int cnt1=0;
	FOR( i , 0 , n-1){
		cin >> v[i];
		
		
	}
	cout << n/2;

    return 0;
}