using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukikoda
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.ReadLine();
            var a = ConvertStringArrayToIntList(Console.ReadLine().Split());
            Console.WriteLine(a.Sum() - long.Parse(Console.ReadLine()));
        }

        static List<int> ConvertStringArrayToIntList(string[] str)
        {
            var list = new List<int>();
            foreach (var c in str) list.Add(int.Parse(c));
            return list;
        }
    }
}