1class RunewordsCalculator:
 2    def __init__(self, runewords):
 3        self.runewords = runewords
 4        self.runes = []
 5        self.runewords_made = set()
 6
 7    def add_runes(self, runes):
 8        self.runes.extend(runes)
 9
10    def __iter__(self):
11        return self
12    
13    def __next__(self):
14        if len(self.runewords_made) == len(self.runewords):
15            raise StopIteration
16        for name, required_runes in self.runewords.items():
17            if name in self.runewords_made:
18                continue
19            index = 0
20            indexes_to_remove = []
21            for rune in required_runes:
22                found = False
23                for i in range(index, len(self.runes)):
24                    if self.runes[i] == rune:
25                        found = True
26                        index = i + 1
27                        indexes_to_remove.append(i)
28                        break
29                if not found:
30                    break
31            if len(indexes_to_remove) == len(required_runes):
32                self.runewords_made.add(name)
33                for i in sorted(indexes_to_remove, reverse=True):
34                    self.runes.pop(i)
35                return name
36        return None