#include <bits/stdc++.h>
using namespace std;
int main() {
  long long b[4], a = 0;
  for (int i = 0; i < 3; i++) cin >> b[i], a += b[i];
  a--;
  for (int i = 0; i < 3; i++)
    for (int j = i + 1; j < 3; j++)
      if (abs(b[i] - b[j]) % 2 == 0) a = min(a, max(b[i], b[j]));
  cout << a;
  return 0;
}
