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 Kotlin (1.0.0) (judge verdict: Runtime Error)

fun main(args: Array<String>) {
  val N = readInt()
  val A = readLongs()

  var lcm = 1L
  A.forEach {
    lcm = lcm(lcm, it)
  }
  var sum = 0L
  A.forEach {
    sum += (lcm - 1) % it
  }
  println(sum)
}

//fun gcd(a: Int, b: Int): Int = if (a < b) gcd(b, a) else if (b == 0) a else gcd(b, a % b)
fun gcd(a: Long, b: Long): Long = if (a < b) gcd(b, a) else if (b == 0L) a else gcd(b, a % b)

//fun lcm(a: Int, b: Int): Int = (a * b) / gcd(a, b)
//fun lcm(a: Long, b: Long): Long = (a * b) / gcd(a, b)
fun lcm(a: Long, b: Long): Long {
  val gcd = gcd(a, b)
  if (gcd == 0L) return -1
  return (a * b) / gcd(a, b)
}

fun readString() = readLine()!!
fun readInt() = readLine()!!.toInt()
fun readInts() = readLine()!!.split(" ").map { it.toInt() }
fun readLongs() = readLine()!!.split(" ").map { it.toLong() }