char* kth_word_in_mth_sentence_of_nth_paragraph(char**** document, int k, int m, int n) {
    return document[n-1][m-1][k-1];
}

char** kth_sentence_in_mth_paragraph(char**** document, int k, int m) { 
    return document[m-1][k-1];
}

char*** kth_paragraph(char**** document, int k) {
    return document[k-1];
}

char**** get_document(char* text) {
    int count_word = 0;
    int count_sentence = 0;
    int count_paragraph = 1;
    int len = strlen(text);
    for(int i = 0; i < len; i++)
    {
        if(text[i] == ' ')
            count_word++;
        else if(text[i] == '.')
        {
            count_word++;
            count_sentence++;
        }
        else if(text[i] == '\n')
            count_paragraph++;
    }
    char** words = (char**) malloc(count_word * sizeof(char*));
    words[0] = text;
    char*** sentences = (char***) malloc(count_sentence * sizeof(char**));
    sentences[0] = words;
    char**** paragraphs = (char****) malloc(count_paragraph * sizeof(char***));
    paragraphs[0] = sentences;
    
    for(int i = 1, i_word = 1, i_sentence = 1, i_paragraph = 1; i < len; i++)
    {
        if(text[i] == ' ')
        {
            text[i] = '\0';
            words[i_word++] = text+i+1;
        }
        else if(text[i] == '.')
        {
            text[i] = '\0';
            if(i_sentence < count_sentence && text[i+1] != '\n')
            {
                words[i_word++] = text+i+1;
                sentences[i_sentence++] = words + i_word - 1;
            }
        }
        else if(text[i] == '\n')
        {
            words[i_word++] = text+i+1;
            sentences[i_sentence++] = words + i_word - 1;
            paragraphs[i_paragraph++] = sentences + i_sentence -1;
        }
    }
    return paragraphs;
}