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)

rom sys import stdin
import fractions

N = int(stdin.readline().rstrip())
A = [int(x) for x in stdin.readline().rstrip().split()]

lcm_a = int(A[0] * A[1] // fractions.gcd(A[0], A[1]))

if len(A) > 2:
    for k in A[2:]:
        lcm_a = int(lcm_a * k // fractions.gcd(lcm_a, k))

modulo_sum = 0

for k in A:
    modulo_sum += (lcm_a - 1) % k

print(modulo_sum)