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 <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <regex>
#define rep(i,n) for(int i = 0; i < n; i++)
#define reps(i,j,n) for(int i = j; i < n; i++)
#define rrep(i,j,n) for(int i = j-1; i >= n; i--)
#define prec(n) fixed << setprecision(n)
#define print_array(v) rep(__k, v.size()) { cout << v[__k]; if(__k != v.size()-1) cout << " "; else cout << endl; }
#define YesorNo(a) printf(a?"Yes\n":"No\n")
#define fi first
#define se second
using namespace std;

int inf = 2147483647;
int64_t inf64 = 9223372036854775807;
int mod = 1e+7;

signed main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n;
  cin >> n;

  int res = 0;
  while(n--) {
    int a;
    cin >> a;
    res += a-1;
  }
  cout << res << endl;
  return 0;
}