using System;
using System.Linq;

namespace PowerPlants_6
{
    public class PowerPlants_6
    {
        public static void Main(string[] args)
        {
            var powerLevel = Console.ReadLine()
                .Split(' ')
                .Select(int.Parse)
                .ToArray();

            var daysInSeason = powerLevel.Length;
            var daysAlive = 0;



            for (int i = 0; i < daysInSeason-1; i++)
            {
                for (int p = 0; p < powerLevel.Length; p++)
                {
                    if (i!=p && powerLevel[p]!=0)
                    {
                        powerLevel[p] = powerLevel[p] - 1;
                    }
                }

                daysAlive++;

                var sum = 0;
                for (int j = 0; j < powerLevel.Length; j++)
                {
                    sum = sum + powerLevel[j];
                }
                if (sum == 0)
                {
                    i = -1;
                }
            }

            Console.WriteLine(daysAlive);

        }
    }
}