//No.91 赤、緑、青の石

import java.util.*;
import java.io.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class No91 {
    
    static final Scanner in = new Scanner(System.in);
    static final PrintWriter out = new PrintWriter(System.out,false);

    static void solve() {
        int[] c = new int[3];
        for (int i=0; i<3; i++) c[i] = in.nextInt();
        sort(c);
        int ans = c[0];
        for (int i=2; i>=0; i--) c[i] -= c[0]; 

        while (c[2] >= 3) {
            c[2] -= 2;
            c[0] += 1;
            sort(c);
            if (c[0] > 0 && c[1] > 0) {
                ans += c[0];
                for (int i=2; i>=0; i--) c[i] -= c[0];
            }
        }

        out.println(ans);
    }

    public static void main(String[] args) {
        long start = System.currentTimeMillis();

        solve();
        out.flush();

        long end = System.currentTimeMillis();
        //trace(end-start + "ms");
        in.close();
        out.close();
    }

    static void trace(Object... o) { System.out.println(deepToString(o));}
}