1def beginning(word):
 2    str_len = len(word)
 3    if str_len % 3 == 0:
 4        step = (str_len // 3)
 5        return word[:step]
 6    elif str_len % 3 == 2:
 7        symbols = (str_len-1)//2
 8        return word[:symbols]
 9    elif str_len % 3 == 1:
10        if str_len % 2 == 0:
11            symbols = (str_len - 2) // 2
12        else:
13            symbols = (str_len - 3) // 2
14        return word[:symbols]
15
16
17def middle(word):
18    str_len = len(word)
19    if str_len % 3 == 0:
20        step = (str_len // 3)
21        return word[step:step*2]
22    elif str_len % 3 == 2:
23        symbols = (str_len-1)//2
24        if str_len % 2 == 1:
25            return word[symbols]
26        else:
27            return word[symbols:symbols+2]
28    elif str_len % 3 == 1:
29        if str_len % 2 == 0:
30            symbols = (str_len - 2) // 2
31            return word[symbols:symbols + 2]
32        else:
33            symbols = (str_len - 3) // 2
34            return word[symbols:symbols + 3]
35
36
37def end(word):
38    str_len = len(word)
39    if str_len % 3 == 0:
40        step = (str_len // 3)
41        return word[step*2:]
42    elif str_len % 3 == 2:
43        symbols = (str_len-1)//2
44        return word[-symbols:]
45    elif str_len % 3 == 1:
46        if str_len % 2 == 0:
47            symbols = (str_len - 2) // 2
48        else:
49            symbols = (str_len - 3) // 2
50        return word[-symbols:]
51
52
53def split_sentence(sentence):
54    word_list = sentence.split()
55    result = []
56    for word in word_list:
57        res_list = [beginning(word), middle(word), end(word)]
58        result.append(tuple(res_list))
59    return result