#include <bits/stdc++.h>
#define ll long long
#define rep(i,x,n) for(ll i=x;i<n;i++)
#define rrep(i,x,n) for(ll i=x;i>=n;i--)
using namespace std;
ll mod=1000000007;
void solve(){
  int n;
  cin>>n;
  int a[n];
  rep(i,0,n) cin>>a[i];
  sort(a,a+n);
  if(n%2==1) cout<<n/2+1<<endl;
  else{
    if(n==2 && a[0]+1==a[1]) cout<<2<<endl;
    else cout<<n/2<<endl; 
  }
}
int32_t main(){
  solve();
}