log.Println(solveFirst(p, 10))

	log.Println(solveFirst(p))

	log.Println(solveFirst(p, 40))

func solveFirst(p polimer) int {
	tmp := strings.Builder{}
	for i := 0; i < 10; i++ {
		for ch := range p.template {
			if ch == len(p.template)-1 {
				tmp.WriteByte(p.template[ch])
				break
			}
			tmp.WriteByte(p.template[ch])
			tmp.WriteByte(p.inserts[p.template[ch:ch+2]])

func solveFirst(p polimer, steps int) int {
	var counter = map[string]int{}
	for ch := range p.template {
		if ch == len(p.template)-1 {
			break
		}
		counter[p.template[ch:ch+2]]++
	}
	for i := 0; i < steps; i++ {
		newcounter := map[string]int{}
		for k, v := range counter {
			newcounter[string(k[0])+string(p.inserts[k])] += v
			newcounter[string(p.inserts[k])+string(k[1])] += v

		p.template = tmp.String()
		tmp.Reset()

		counter = newcounter

	chars := map[byte]int{}

	chars := map[rune]int{}
	for _, ch := range p.template {
		chars[ch]++

	// last item in the template skipped on counting, put it back!
	chars[p.template[len(p.template)-1]]++
	for twoChars, v := range counter {
		chars[twoChars[0]] += v