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: Time Limit Exceeded)

require 'prime'
N = gets.chomp.to_i
if N.prime?
	puts N-1
else
  	factors = N.prime_division
  M = Math.sqrt(N).floor
  if M <= factors.last[0]
	while M <= factors.last[0] do
  	if N % M ==0
    	break
  	end
  	M += 1
	end
  else
    while M >= 1 do
      if N % M ==0
    	break
  	  end
  	  M -= 1
	end
  end
	puts (M + N/M -  2)
end