import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner scan = new Scanner(System.in)) {
            int v[] = new int[3];
            v[0] = Integer.parseInt(scan.next());
            v[1] = Integer.parseInt(scan.next());
            v[2] = Integer.parseInt(scan.next());
            while(true) {
                Arrays.sort(v);
                if((v[0] == v[1] && v[0] == v[2]) || (v[2]-v[0] == 1)) {
                    System.out.println(v[0]);
                    return;
                }
                v[2] -= 2;
                v[0] += 1;
            }
        }
    }
}