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: Wrong Answer)

N = int(input())
def trial_division(n):
    a = []  
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2   
    if n != 1: a.append(n)
    return a

T = trial_division(N)
D = {}
for t in T :
    if t not in D :
        D[t] = 1
    else :
        D[t] += 1

S = set()
for t in T :
    for i in range(D[t]+1) :
        if t**i == 1 or t**i == N :
            S.add((t**i)+(N//(t**i))-2)
        else :            
            S.add((t**i)+(N//(t**i))-2)
ans = min(list(S))
print(ans)