#include <bits/stdc++.h>
using namespace std;
long long INF = 1000000000000000000LL;
long long calc(long long a, long long b, long long c) {
  if ((a % 2) != (b % 2)) return INF;
  return max(a, b);
}
int MAIN() {
  long long a, b, c;
  while (cin >> a >> b >> c) {
    long long ans = INF;
    ans = min(ans, calc(a, b, c));
    ans = min(ans, calc(a, c, b));
    ans = min(ans, calc(b, c, a));
    cout << ans << endl;
  }
  return 0;
  ;
}
int main() {
  ios ::sync_with_stdio(false);
  cout << fixed << setprecision(16);
  return MAIN();
}
