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.

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.

Constraints

• $2 \leq N \leq 10^{12}$
• N is an integer.

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.

见题面 Input 部分

见题面 Output 部分