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: Runtime Error)

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

namespace ConsoleApp1
{
	class Program
	{
		static void Main(string[] args)
		{
			Console.ReadLine();
			var nums = Console.ReadLine().Split(' ').Select(input => decimal.Parse(input));

			decimal commonMultiple = 1;

			foreach (var num in nums)
			{
				commonMultiple = calculateCommonMultiple(commonMultiple, num);
			}
			Console.WriteLine(f(nums, commonMultiple - 1));
		}

		private static decimal calculateCommonMultiple(decimal current, decimal next)
		{
			if (current % next == 0)
			{
				return current;
			}
			if (next % current == 0)
			{
				return next;
			}
			return current * next;
		}

		private static decimal f(IEnumerable<decimal> nums, decimal m) => nums.Sum(num => m % num);
	}
}