#include<bits/stdc++.h>
using namespace std;
int main()
{
long long a,b,c,d;
int max=0;
if((a % 2 == 0) && (max<a))
max = a;
if((b % 2 == 0) && (max<b))
max = b;
if((c % 2 == 0) && (max<c))
max = c;
if((d % 2 == 0) && (max<d))
max = d;
if(max == 0)
cout<<"none";
else
cout<<max;
return 0;
}