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

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args) {
            int N = int.Parse(Console.ReadLine());
            string[] Key = Console.ReadLine().Split(' ');
            int[] Mods = new int[N];
            for(int i = 0; i < N; i++) {
                Mods[i] = int.Parse(Key[i]);
            }
            Array.Sort(Mods);
            int LCM = 1;
            for (int i = 0; i < Mods.Length; i++) {
                if (LCM > Mods[i]) {
                    LCM *= getLCM(LCM, Mods[i]);
                } else {
                    LCM *= getLCM(Mods[i], LCM);
                }
                if (i == 0) i++;
            }
            int answer = 1;
            for (int i = 1; i < LCM; i++) {
                answer = Math.Max(answer, Mod(i, Mods));
            }
            Console.WriteLine(answer);
        }

        static int getGCD(int m, int n) {
            if (n == 0) return m;
            return getGCD(n, n % m);
        }

        static int getLCM(int m, int n) {
            return m * n / getGCD(m, n);
        }
        static int Mod(int m,int[] Mods) {
            int sum = 0;
            int N = Mods.Length;
            for(int i = 0; i < N; i++) {
                sum += m % Mods[i];
            }
            return sum;
        }
    }
}