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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(void){
 int n,i,j,ans,flag=0,min=20000000;
 scanf("%d",&n);

//素数の判別プログラム
 for(i=2;i<n;i++){
  if(n%i==0){
    flag=1;
    break;
  }
 }
//素数の場合
 if(flag==0)printf("%d",n-1);
 
 else if(flag==1){
 //掛け算の表の計算
 for(i=1;i<=n/4;i++){
  for(j=1;j<=n/2;j++){
    if(n==i*j){
      ans=i+j-2;
      if(min>ans)min=ans;
      ans=min;
    }
  }
 }
if(ans!=0){
 printf("%d",ans);
  }
}

  return 0;
}