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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <algorithm>
#include <numeric>
#include <map>
#define rep(i, n) for(int i=0;i<(int)(n);i++)
#define pb(a) push_back(a)
#define MAX(a, b) ((a < b)?b:a)
#define MIN(a, b) ((a > b)?b:a)
typedef long long int ll;
typedef unsigned long long int ull;
using namespace std;

ull gcd(ull a, ull b) { return b ? gcd(b, a%b) : a; }
ull lcm(ull m, ull n) {	return ((0 == m) || (0 == n)) ? 0 : ((m / gcd(m, n)) * n); }

int main()
{
	ull sum = 0;
	ull n;
	cin >> n;
	rep(i, n)
	{
		ull an;
		cin >> an;
		sum += an - 1;
	}

	cout << sum << endl;

	return 0;
}