#include<stdio.h>
int main(){
   int arr[3];
   for(int i=0;i<3;i++){
    scanf("%d",&arr[i]);
   }
   if((arr[0]+arr[1])%2==0)
    printf("%d",arr[2]);
   else if((arr[0]+arr[2])%2==0)
    printf("%d",arr[1]);
   else
   printf("%d",arr[0]);
}