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>
int gcd(int a, int b)
{
    if(b==0)
        return a;
    return gcd(b,a%b);
}
int lcm( int a, int b)
{
    return a*b/(gcd(a,b));
}
int main()
{
    int n,i;
    scanf("%d",&n);
    long long int a[n],sum=0,l;
    for(i=0;i<n;i++)
        scanf("%lld",&a[i]);
    l=a[0];
    for(i=0;i<n;i++)
        l=lcm(l,a[i]);
    l=l-1;
    for(i=0;i<n;i++)
        sum+=l%a[i];
    printf("%lld",sum);
}