#include <bits/stdc++.h>
int main() {
  int a, b, c, t;
  scanf("%d%d%d", &a, &b, &c);
  if (a > b) {
    t = a, a = b, b = t;
  }
  if (a + c <= b)
    printf("%d\n", 2 * (a + c));
  else {
    if ((a + b + c) % 2)
      printf("%d\n", a + b + c - 1);
    else
      printf("%d", a + b + c);
  }
  return 0;
}
