#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long a, b, c;
  auto f = [](long long a, long long b) {
    return ((a + b) & 1) ? (long long)1e18 : max(a, b);
  };
  cin >> a >> b >> c, cout << min({f(a, b), f(b, c), f(c, a)}) << '\n';
}
