class Integer
	def isqrt
		return 0 if self<=0
		return 1 if self<4 # 1
		x,y=0,self
		while x!=y&&x+1!=y
			x,y=y,(self/y+y)/2
		end
		x
	end
end
n=gets.to_i
s=n.isqrt
p 2*s-(n/s==s ? 1 : 0)