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

typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef pair<ll, ll> pi;
typedef pair<char, ll> pci;
typedef vector<pi> vii;
typedef map<ll, ll> mi;
typedef set<ll> seti;

#define sz size()
#define ins insert
#define mp make_pair
#define pb push_back
#define nl << "\n";
#define all(x) x.begin(), x.end()
#define db(x) cout << #x << " = " << x nl
#define input(x) for (auto &a : x) cin >> a;
#define view(x) cout << #x << ": "; for (auto a : x) {cout << a << " ";} cout nl
#define viewp(x) cout << #x << ": "; for (auto a : x) {cout << a.first << " " << a.second nl}

void solve() {
    ll n;
    cin >> n;
    if (n & 1 == 1) {
        cout << n - 1 nl
    } else {
        cout << n nl
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    ll t = 1;
    //cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}