>>473
#include<iostream>
void swap(int *a, int *b){
int c;
c=*a; *a=*b; *b=c;
}
int main(void){
int max1=0, max2=0, num;

while(std::cin >> num){
if(num==0) break;
if(num<0 || num%2==1) continue;
if(num>max2) max2=num;
if(max1<max2) swap(&max1, &max2);
}
std::cout << max2 << std::endl;
return 0;
}