import math
import sys

n = int(input())

l = []
if n == 2:
    print(1)
    sys.exit()
else:
    for i in range(2, int(math.sqrt(n) + 1)):
        if n % i == 0:
            for i in range(1, int(math.sqrt(n)) + 1):
                if n % i == 0:
                    j = n // i
                    l.append(i + j)
            print(min(l) - 2)
            sys.exit()
print(n -1)