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 Python (3.4.3) (judge verdict: Accepted)

N = int(input())

# 約数の全列挙
def divisors(n):
    divisors = []
    R = int(n**(0.5)) + 1
    for i in range(1, R):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n // i)
    # divisors.sort(reverse=True)  # ソート
    return divisors

ans = 10**18
for d in divisors(N):
    k = N // d

    ans = min(ans, d + k - 2)
print(ans)