using System;
using System.Collections.Generic;
using System.Linq;

namespace yukicoder
{
    public class Program
    {
        public static void Main()
        {
            var s = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
            var sum = 0;
            sum = Make(s, sum);
            Console.WriteLine(sum);
        }
        public static int Make(int[] s,int sum)
        {
            Array.Sort(s);
            sum += s[0];
            s = s.Select(x => x - s[0]).ToArray();
            if (!s.All(x => x < 3))
            {
                var k = (s[2] - s[1]) / 2;
                if (k == 0)
                {
                    k = s[2] / 4;
                }
                if (k == 0)
                {
                    k = 1;
                }
                s = new int[3] { k, s[1], s[2] - k * 2 };
                sum = Make(s, sum);
            }
            return sum;
        }
    }
}