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: Accepted)

import java.math.BigInteger

private fun readStrings() = readLine()!!.split(" ")
private fun readInts() = readStrings().map { it.toInt() }

fun main(args: Array<String>) {
    val N = readInts()[0]
    val a = readInts()
    val bigA = a.map { BigInteger.valueOf(it.toLong())!! }
    val p = bigA.reduce { i1, i2 -> i1.multiply(i2) }
    val q = p.minus(BigInteger.valueOf(1))
    val ans = bigA.map { q.mod(it) }.reduce { i1, i2 -> i1 + i2 }
    println(ans.toString(10))
}