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<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
    ll n;   cin >> n;
    vector<ll> a(n);
    ll sum=1;
    for(int i=0; i<n; i++){
        cin >> a.at(i);
        sum *= a.at(i);
    }
    sort(a.begin(), a.end());
    bool flag=true;
    for(int i=1; i<n; i++){
        if(a[i]%a[0]==0) continue;
        flag = false;
    }
    if(flag) sum /= a[0];

    ll ans=0;
    for(int i=0; i<n; i++)  ans += (sum-1)%a[i];
    
    cout << ans << endl;
}