Problem:
Score : 300 points

Problem Statement

Takahashi is standing on a multiplication table with infinitely many rows and columns.

The square (i,j) contains the integer i \times j. Initially, Takahashi is standing at (1,1).

In one move, he can move from (i,j) to either (i+1,j) or (i,j+1).

Given an integer N, find the minimum number of moves needed to reach a square that contains N.

Constraints

2 \leq N \leq 10^{12}

N is an integer.

Input

Input is given from Standard Input in the following format:

N

Output

Print the minimum number of moves needed to reach a square that contains the integer N.

Sample Input 1

10

Sample Output 1

5

(2,5) can be reached in five moves. We cannot reach a square that contains 10 in less than five moves.

Sample Input 2

50

Sample Output 2

13

(5, 10) can be reached in 13 moves.

Sample Input 3

10000000019

Sample Output 3

10000000018

Both input and output may be enormous.

Solution in Ruby (2.3.3) (judge verdict: Wrong Answer)

require 'prime'
def search factors
  if factors.length == 1
    puts factors[0] - 1
  elsif factors.length == 2
    puts factors[0]-1 + factors[1]-1
  else
    min_1 = factors.min
    factors.delete_at(factors.find_index(min_1))
    min_2 = factors.min
    factors.delete_at(factors.find_index(min_2))
    factors.push(min_1 * min_2)

    search(factors)
  end
end


n = gets.to_i
factors = n.prime_division.map {|p, e| [p] * e }.flatten
search(factors)