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: Accepted)

#                         author:  kagemeka 
#                         created: 2019-11-08 15:54:47(JST)
### modules
## from standard library
import sys
# import collections
# import math
# import string
# import bisect
# import re
# import itertools
# import statistics
import functools
# import operator
## from external libraries
# import scipy.special   # if use comb function on AtCoder, 
# import scipy.misc      # select scipy.misc.comb (old version) 
# import numpy as np

def gcd(a, b):
    while b != 0:
        a, b = b, a % b
    return a

def lcm(a, b):
    return a * b // gcd(a, b)


def main():
    n, *a = (int(x) for x in sys.stdin.read().split())

    m = functools.reduce(lcm, a)
    f = sum([(m - 1) % a[i] for i in range(n)])
    print(f)

if __name__ == "__main__":
    # execute only if run as a script
    main()