#include <bits/stdc++.h>
using namespace std;
int main() {
  long long nums[3];
  cin >> nums[0] >> nums[1] >> nums[2];
  sort(nums, nums + 3);
  if ((nums[1] - nums[0]) % 2 != 0) {
    cout << nums[2] << endl;
  } else {
    cout << nums[1] << endl;
  }
  return 0;
}
