func main()
	var n: int :: cui@inputInt()
	var s: []char :: cui@inputStr()
	var ans: bool :: false
	for i(0, n - 1)
		for j(i + 1, n - 1)
			if(s[i] = s[j])
				do ans :: true
			end if
		end for
	end for
	do cui@print((ans ?("Yes", "No")) ~ "\n")
end func