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 <string.h>

int main(void)
{
	long long a=1, b, r, x, tmp,c[3001],d[3001],y=0;
	int i,n;
	scanf("%d",&n);
	for(i=0;i<n;i++){
		scanf("%d",&c[i]);
	}
	memcpy(d,c,sizeof(c));
	for(i=0;i<n;i++){
		x = a * c[i];
  		if(a<c[i]){
			tmp = a;
    		a = c[i];
    		c[i] = tmp;
  		}
  		r = a % c[i];
  		while(r!=0){
    		a = c[i];
    		c[i] = r;
    		r = a % c[i];
  		}
		a=x/c[i];
 	}
	for(i=0;i<n;i++){
		y=y+(a-1)%d[i];
	}
	printf("%d\n",y);
  	return 0;
}