package no091;

import java.util.Scanner;

public class Main {
	public static final int MAX = 10000000;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] n = new int[3];
		for(int i=0;i<3;i++) {
			n[i] = sc.nextInt();
		}
		while(true) {
			int maxi = -1;
			int mini = -1;
			int max = -1<<29;
			int min = 1<<29;
			for(int i=0;i<3;i++) {
				if (n[i] < min) {
					min = n[i];
					mini = i;
				}else if(n[i] > max) {
					max = n[i];
					maxi = i;
				}
			}
			if (max - min <= 2) {
				break;
			}
			if (n[maxi] <= 2) {
				break;
			}
			n[mini]++;
			n[maxi]-=2;
		}
		System.out.println(Math.min(n[0],Math.min(n[1],n[2])));
	}

}