func main()
	var n: int :: cui@inputInt()
	var s: []char :: cui@input()
	var cnt: int :: 0
	for i(0, n - 1)
		switch(s[i])
		case 'H'
			do cui@print("-1\n")
			ret
		case 'Q'
			do cnt :+ 1
		end switch
	end for
	var sqrt: int :: 0
	for i(1, n)
		if(i ^ 2 = cnt)
			do sqrt :: i
		end if
	end for
	if(sqrt = 0)
		do cui@print("-1\n")
		ret
	end if
	var sub: []char :: s.sub(0, n / sqrt)
	if(sub.repeat(sqrt) = s)
		do cui@print("\{sub}\n")
	else
		do cui@print("-1\n")
		ret
	end if
end func