Problem:
Score : 300 points

Problem Statement

You are given N positive integers a_1, a_2, ..., a_N.

For a non-negative integer m, let f(m) = (m\ mod\ a_1) + (m\ mod\ a_2) + ... + (m\ mod\ a_N).

Here, X\ mod\ Y denotes the remainder of the division of X by Y.

Find the maximum value of f.

Constraints

All values in input are integers.

2 \leq N \leq 3000

2 \leq a_i \leq 10^5

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the maximum value of f.

Sample Input 1

3
3 4 6

Sample Output 1

10

f(11) = (11\ mod\ 3) + (11\ mod\ 4) + (11\ mod\ 6) = 10 is the maximum value of f.

Sample Input 2

5
7 46 11 20 11

Sample Output 2

90

Sample Input 3

7
994 518 941 851 647 2 581

Sample Output 3

4527

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
    class Program
    {
        static void Main(string[] args)
        {
            string N = Console.ReadLine();
            List<int> a = Console.ReadLine().Split(' ').Select(int.Parse).ToList();

            int LowestCommonMultiple = 1;
            int GreatestCommonFactor = 0;

            for (int i = a.Min(); 0 < i; i--)
            {
                for(int j = 0; j < a.Count; j++)
                {
                    if(a[j] % i != 0)
                    {
                        goto Next;
                    }                    
                }
                GreatestCommonFactor = i;
                break;

                Next:;
            }
            
            for(int i =0; i < a.Count; i++)
            {
                LowestCommonMultiple *= a[i];
            }

            int val = 0;
            for(int j = 0; j < a.Count; j++)
            {
                val += (LowestCommonMultiple - 1) % a[j]; 
            }
            
            Console.WriteLine(val);
        }
    }