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

namespace ConsoleApp90 {
    class Program {
        static void Main(string[] args) {
            int N = int.Parse(Console.ReadLine());
            var a = new int[N];

            Console.WriteLine(a.Sum() - N);


        }
    }
}