MOD=10**9+7
cnt=0; sum=0; prev=nil; can=true; h=Hash.new(0)
def gs() gets.chomp end
def gi() gets.to_i end
def gsmi() gets.chomp.split.map(&:to_i) end

def desc(ar) ar.sort!{|x,y|y<=>x} end
def min(a,b) a<=b ? a : b end
def max(a,b) a>=b ? a : b end
def sum(ar) ar.inject(:+) end

def C(a,b) b==0||a==b ? 1 : (b=a-b if a/2<b;(a-b+1..a).inject(:*)/(1..b).inject(:*)) end

def puts_yesno(can) puts(can ? 'Yes' : 'No') end
def putsend(s) puts s; exit end
def debug(k,v) puts "#{k}:#{v}" end
########### ( ˘ω˘ )ｽﾔｧ… ###########
n=gi

require 'prime'

ar=[]
np=n.prime_division
# np.each do |a,b|
#   temp=[1]
#   b.times do |i|
#     temp<<a*(i+1)
#   end
#   ar<<temp
# end

def div(pr,k=0)
  Enumerator.new do |en|
    if pr.size == k
      en << 1
    else
      p,e = pr[k]
      div(pr,k+1).each do |d|
        (e+1).times do |e1|
          en << (p**e1) * d
        end
      end
    end
  end
end

divs=div(np).to_a

#puts divs.to_s

sq=Math.sqrt(n).to_i
res=1
divs.each do |d|
  if d<=sq
    res=d
  else
    break
  end
end

puts res+(n/res)-2