import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int R = sc.nextInt();
    int G = sc.nextInt();
    int B = sc.nextInt();
    int ans = 0;
    int l = 0;
    int r = 10000001;
    while(l < r) {
      int med = (l + r) / 2;
      int plus = 0;
      int minus = 0;
      if(R >= med) {
        plus += ((R - med) / 2);
      } else {
        minus += (med - R);
      }

      if(G >= med) {
        plus += ((G - med) / 2);
      } else {
        minus += (med - G);
      }

      if(B >= med) {
        plus += ((B - med) / 2);
      } else {
        minus += (med - B);
      }

      if(plus >= minus) {
        ans = med;
        l = med + 1;
      } else {
        r = med;
      }
    }
    System.out.println(ans);
  }
}