#include <stdio.h>

int main(void) {
  int r, b, w, max, min;
  scanf("%d %d %d", &r, &b, &w);

  if (r>=b) {
    max=r;
    min=b;
  } else {
    max=b;
    min=r;
  }

  int dif;
  dif=max-min;
  if (dif<=w) {
    w-=dif;
    min+=dif+(w/2);
  } else {
    min+=w;
  }

  printf("%d\n", min);
  return 0;
}