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 <limits.h>

int main()
{
    int n, i;
    long  tmp, g, x, y;
    scanf("%d", &n);

    long a[n];
    long c[n];
    long plus = 1;

    long ans=0;

    scanf("%ld", &a[0]);
    c[0] = a[0];
    plus = a[0];

    for(i=1; i<n; i++)
    {
        scanf("%ld", &a[i]);
        c[i] = a[i];
        x = plus * a[i];
        if(plus<a[i])
        {
            tmp = plus;
            plus = a[i];
            a[i] = tmp;
        }
        g = plus % a[i];
        while(g!=0)
        {
            plus = a[i];
            a[i] = g;
            g = plus % a[i];
        }
        plus = x / a[i];
    }

    plus = plus - 1;

    for(i=0; i<n; i++)
    {
        ans = ans + (plus%c[i]);
    }

    printf("%ld\n", ans);

    return 0;
}