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>
#include <string.h>

int main(void){
    // Your code here!
    int a[3000],N,amax = -1;
    unsigned long fmax = 0,temp;
    scanf("%d",&N);
    for(int i = 0; i < N; i++)
    {
        scanf("%d",&a[i]);
        if(amax < a[i]) amax = a[i];
    }
    //printf("amax: %d\n", amax);
    for(int i = 1; i < 100000; i++)
    {
        temp = 0;
        for(int j = 0; j < N; j++)
        {
            temp += ((i*amax)-1)%a[j];
        }
        
        //printf("%d: %ld\n", i,temp);
        if(temp > fmax) fmax = temp;
    }
    
    printf("%ld\n",fmax);
}