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 Go (1.6) (judge verdict: Accepted)

package main
import "fmt"


func gcd(a, b int) int {
	for b != 0 {
		return gcd(b, a%b)
	}
	return a
}

func main() {
	var n int
	fmt.Scan(&n)
	var a []int
	var ans int64 = 0
	for i := 0; i < n; i++ {
		var v int
		fmt.Scan(&v)
		a = append(a, v)
	}

	var g int = 1
	for _, v := range a{
		g = gcd(g, v)
	}

	for _, v := range a{
		ans += int64(v / g -1)
	}

	fmt.Println(ans)
}