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;
using System.Text;
using System.Threading.Tasks;

namespace test
{
    class Program
    {
        static void Main(string[] args)
        {
            var N = int.Parse(Console.ReadLine());
            var A = Console.ReadLine().Split(' ').Select(s => long.Parse(s)).ToArray();
            var tmpLcm = A[0];
            for (var i = 1; i < N; i++) tmpLcm = Lcm(tmpLcm, A[i]);
            tmpLcm--;
            var ans = 0L;
            for (var i = 0; i < N; i++) ans += tmpLcm % A[i];

            Console.WriteLine(ans);
        }

        public static long Gcd(long a,long b)
        {
            if (b == 0) return a;

            return Gcd(b, a % b);            
        }

        public static long Lcm(long a,long b)
        {
            return a * b / Gcd(a, b);
        }
    }
}