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 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
#include<stdlib.h>

long gcd(int m, int n)
{
	int temp;
	while(m % n != 0){
		temp = n;
		n = m % n;
		m = temp;
	}

	return n;
}

long lcm(int m, int n)
{
	return m * n / gcd(m,n);
}

long lcm_n(long* nu, long n)
{
	long l;
	int i;

	l = *nu;

	for(i=0;i<n;i++){
		l = lcm(l, nu[i]);
	}

	return l;
}

int main()
{
	long n, g, f;
	int i;
	long *num;
	scanf("%d", &n);

	num = (long*)malloc(sizeof(int)*n);
	for(i=0;i<n;i++){
		scanf("%d", &num[i]);
	}

	g = lcm_n(num,n) - 1;
	f = 0;

	for(i=0;i<n;i++){
		f += g % num[i];
	}

	printf("%d\n", f);

	return 0;
}