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 Python (3.4.3) (judge verdict: Runtime Error)

# -*- coding: utf-8 -*-
import sys
from functools import reduce
from math import gcd
# ----------------------------------------------------------------
# Use Solve Function

def solve(lines):
    N = int(lines.pop(0))
    A = list(map(int, lines.pop(0).split(' ')))
    lcd = reduce(lambda i,j: i*j//gcd(i,j), A, 1)
    m = lcd - 1
    A = [ m % i for i in A ]
    print(sum(A))

lines = [x.strip() for x in sys.stdin.readlines()]

#
# solve !!
#
solve(lines)