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: Accepted)

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <functional>
#include <bitset>
#include <cmath>
#include <stack>
#include <iomanip>
#include <map>
#include <math.h>
typedef long long ll;
using namespace std;
const int MOD = 1000000007;

ll GCD(ll a, ll b) { return b ? GCD(b, a%b) : a; }

int main()
{
    int N;
    cin >> N;
    ll a[N];
    for(int i = 0; i < N; i++) cin >> a[i];

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