import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int[] values = new int[3];
        for (int i = 0; i < 3; i++) {
            values[i] = sc.nextInt();
        }
        int left = 0;
        int right = Integer.MAX_VALUE / 2;
        while (right - left > 1) {
            int m = (left + right) / 2;
            int current = 0;
            for (int i = 0; i < 3; i++) {
                if (values[i] < m) {
                    current -= m - values[i];
                } else {
                    current += (values[i] - m) / 2;
                }
            }
            if (current < 0) {
                right = m;
            } else {
                left = m;
            }
        }
        System.out.println(left);
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}