#include <bits/stdc++.h>
using namespace std;
void mSwap(unsigned int* a, unsigned int* b) {
  *a = *a ^ *b;
  *b = *a ^ *b;
  *a = *a ^ *b;
}
void mSort(unsigned int* a, unsigned int* b, unsigned int* c) {
  if (*a < *b) {
    mSwap(a, b);
  }
  if (*c > *a) {
    mSwap(a, c);
    mSwap(b, c);
  } else if (*c > *b) {
    mSwap(b, c);
  }
}
int main() {
  unsigned int a, b, c, sum = 0;
  cin >> a >> b >> c;
  mSort(&a, &b, &c);
  if ((b - c) % 2) {
    cout << a << endl;
  } else
    cout << b << endl;
  return 0;
}
