import collections
A= int(input())

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    # divisors.sort()
    return divisors
  
primelist=make_divisors(A)
S = primelist[-1]
G = int(A/S)
print((G-1)+(S-1))