#include <bits/stdc++.h>
using namespace std;
inline long long read() {
  long long x = 0, f = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    x = (x << 1) + (x << 3) + (c ^ 48);
    c = getchar();
  }
  return x * f;
}
signed main() {
  long long a = read(), b = read(), c = read();
  if (b > c) swap(b, c);
  if (a > b) swap(a, b);
  if (b > c) swap(b, c);
  if ((b - a) % 2)
    printf("%lld", c);
  else
    printf("%lld", b);
  return 0;
}
