func main()
	var n: int :: cui@inputInt()
	var a: []int :: math@primeFactors(n)
	var ans: int
	if(^a = 1)
		do ans :: a[0]
	else
		if(a[0] = 2)
			if(a[1] = 2)
				do ans :: 4
				for i(2, ^a - 1)
					if(a[i] = 3)
						do ans :: 3
					end if
				end for
			else
				do ans :: a[1]
			end if
		else
			do ans :: a[0]
		end if
	end if
	do cui@print("\{ans}\n")
end func