#include<algorithm>
#include<typeinfo>
#include<stdlib.h>
#include<string.h>
#include<iostream>
#include<iomanip>
#include<stdio.h>
#include<math.h>
#include<string>
#include<vector>
#include<queue>
#include<stack>
#include<map>
#include<set>
#include<iterator>
#include<functional>
#define eps 0.01
#define pi acos(-1)
#define e exp(1)
using namespace std;
typedef long long ll;
int main() {
    ll n;
    while (cin >> n) {
        if (n & 1)
            n *=2;
        cout << n << endl;
    }
    return 0;
}