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;
class Program{
	static void Main(){
		int n=int.Parse(Console.ReadLine());
		long[] s=Array.ConvertAll(Console.ReadLine().Split(),long.Parse);
		long[] a=new long[n];
		a[0]=s[0];
		long b,c=0;
		
		for(int i=1;i<n;i++){
			a[i]=(a[i-1]*s[i]/gcd(a[i-1],s[i]));
		}
		b=a[n-1]-1;

		for(int i=0;i<n;i++){
			c+=b%s[i];
		}
		
		Console.WriteLine(c);
	}
	static long gcd(long a,long b){
		long c=Math.Max(a,b)%Math.Min(a,b);
		b=Math.Min(a,b);
		while(c!=0){
			a=b%c;
			b=c;
			c=a;
		}
		return b;
	}
}