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 <cstdio>
#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <map>
#include <set>

#define MIN_INT -2147483648
#define MAX_INT 2147483647
#define MIN_LONG -9223372036854775808L
#define MAX_LONG 9223372036854775807L
#define PI 3.141592653589793238462643383279502884L

#define long long long int

using std::vector;
using std::map;
using std::set;
using std::string;
using std::pair;
using std::cin;
using std::cout;
using std::cerr;

// @author: pashka

int main() {
    std::ios::sync_with_stdio(false);

    int n;
    cin >> n;
    long m = 0;
    for (int i = 0; i < n; i++) {
        int x;
        cin >> x;
        m += x - 1;
    }
    cout << m << "\n";

    return 0;
}