#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define nl "\n"
#define yes <<"YES\n"
#define no <<"NO\n"
#define sp " "
void solve()
{
  ll n ; cin>>n;
  //cout<<"heo\n";
  //cout<<n;
  for(int i=2;i<=n;i++){
    if(i%2==0){
        cout<<i;
        return;
    }
  }

}

int main()
{
       ios_base::sync_with_stdio(false);
       cin.tie(NULL);
    ll t=1; //cin>>t;
    for(ll i =0;i<t;i++) solve(); 
    return 0;
}