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;
class Program
{
	static void Main(string[] args)
	{
		string str = Console.ReadLine();
		long N = long.Parse(str);
		string[] str2 = Console.ReadLine().Split();
		long[] A = new long[N];
		for(var i=0;i<N;i++){
			A[i] = long.Parse(str2[i]);
		}
		long lcma = 1;
		for(var i=0;i<N;i++){
			lcma = Lcm(lcma,A[i]);
		}
		long ans = 0;
		for(var i=0;i<N;i++){
			ans += (lcma -1)% A[i];
		}
		Console.WriteLine(ans);
	}
	
		public static long Lcm(long a, long b) {
            return a * b / Gcd(a, b);
        }
		
		public static long Gcd(long a, long b) {
		if (a < b)
			return Gcd(b, a);
		while (b != 0) {
			var remainder = a % b;
			a = b;
			b = remainder;
		}
		return a;
		}
}