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