#include<bits/stdc++.h>
usinh namespace std;
int main(){
	
	int i;
	cin>>i;
	if(i%2==0) cout<<i;
	
	reurn 0;
}
/**************************************************************
	Problem: 1033
	User: huangyaojie3
	Language: C++
	Result: Compile Error
****************************************************************/