#include <bits/stdc++.h>
using namespace std;
const int INF = 1029384756;
const double PI = acos(-1);
const double EPS = 0.0000000304;
pair<long long, int> ip[3];
int main() {
  scanf("%I64d%I64d%I64d", &ip[0].first, &ip[1].first, &ip[2].first);
  ip[0].second = 0;
  ip[1].second = 1;
  ip[2].second = 2;
  sort(ip, ip + 3);
  if ((ip[0].first % 2) == (ip[1].first % 2) &&
      (ip[1].first % 2) == (ip[2].first % 2)) {
    long long t = ip[1].first;
    printf("%I64d", t);
  } else if (ip[0].first % 2 == ip[1].first % 2) {
    printf("%I64d", ip[1].first);
  } else if (ip[1].first % 2 == ip[2].first % 2) {
    printf("%I64d", ip[2].first);
  } else {
    printf("%I64d", ip[2].first);
  }
  return 0;
}
