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: Time Limit Exceeded)

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

int f(int *a, int n, int m);

int main(void)
{
  int n,a[100000],i,max;
  scanf("%d",&n);
  for(i=0;i<n;i++)
  {
    scanf("%d",&a[i]);
  }



  max=f(a,n,0);
  for(i=0;i<100000000;i++)
  {
    if(f(a,n,i)>max) max=f(a,n,i);
  }
    printf("%d\n",max);
  return 0;
}

int f(int *a, int n, int m)
{
  int fm=0,i;
  for(i=0;i<n;i++)
  {
    fm+=m%a[i];
  }
  return fm;
}