#include<stdio.h>
int main(){
int n,k,s;
int flag;
scanf("%d%d%d",&n,&k,&s);
if((n%2==0 && k%2==0 && s%2!=0) || (n%2!=0 && k%2!=0 && s%2==0))
printf("%d\n",s);
if((n%2==0 && s%2==0 && k%2!=0)||(n%2!=0 && s%2!=0 && k%2==0))
    printf("%d\n",k);
if((k%2==0 && s%2==0 && n%2!=0)||(k%2!=0 && s%2!=0 && n%2==0))
   printf("%d\n",n);
return 0;
}