#include <bits/stdc++.h>
using namespace std;

int main() {
	int n,k,m;
	cin>>n>>k>>m;
	 if(n%2== k %2){
	     cout<<m<<endl;
	 }
	 else if(n%2 == m%2){
	     cout<<k<<endl;
	 }
	 else{
	     cout<<n<<endl;
	 }

}