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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)


#include <stdio.h>

int a[3000];

typedef long long ll;

ll gcd(ll a, ll b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
ll lcm(ll a, ll b) {
  return a*b / gcd(a, b);
}

int main() {
  int N;
  scanf("%d", &N);
  for (int i=0; i<N; i++) {
    scanf("%d", &a[i]);
  }
  
  long long l = a[0];
  for (int i=1; i<N; i++) {
    l = lcm(l, a[i]);
  }
  
  long long acc = 0;
  for (int i=0; i<N; i++) {
    acc += (l-1) % a[i];
  }
  printf("%d\n", (int)acc);
}