         module20927_7(),
         module20927_9(),
         label(
-            "<h3>About how to study here</h3>"),
+            "<h3>How to study here</h3>"),
         work_with_site(),
         module20927_13(),
         module20927_15(),

        </pre>
        
        <h3>Ideology</h3>
        <p>The scores for the task grow very quickly, especially so that at high levels it is not so important that you solve at lower levels. For example, if you are already at level 5, then most likely, level 1 tasks do not pose any difficulty at all for you. Therefore, it does not matter how much you have solved at level 1. And this is due to the fact that level 5 tasks cost much more than level 1 tasks.</p>
        
        <h2>Activity</h2>
        <p>(The specific calculation code is at the same link)</p>
        
        <p>Activity is an indicator of how actively you have been solving problems lately. Every task that you have ever solved gives its contribution to activity. Each task has "basic" activity scores — this is the square root of the level number. (All level 1 tasks have a "base" score of 1, each level 2 task has a base score of 1.4, etc.) This base score is multiplied by $0.55^{t/\tau}$, where $t$ is the time elapsed since you passed this task, and $\strut\tau$ is equal to 1 week. For example, if you have just passed the task, then the base score is taken into account in full. If you passed the task exactly a day ago, then the base score is multiplied by $0.55^{1/7}\approx 0.92$. If you passed the task exactly two weeks ago, then the base score is multiplied by $0.55^2\approx.3$. If you passed the task 8 weeks ago, then the base score is multiplied by $0.55^8\approx.0083$, i.e. this task is almost not taken into account.</p>
        
        <p>The total activity value for all tasks is divided by 0.45, resulting in a sort of average number of "tasks" per week.</p>
        
        <p>It turns out that in fact only recently completed tasks are taken into account, and those that you have solved for a long time are not taken into account. But at the same time, the decline in this "accountability" is smooth. If you stop solving problems, then your activity will gradually decrease over time (although it will never become exactly zero). In the tables, activity is displayed rounded to one decimal place, but in fact, activity is a real real number.</p>
        
        <p>In a number of summary tables, students whose activity is greater than 0.1 are indicated first, and only then all the others.</p>
        
        <h2>Colour</h2>
        <p>The names of schoolchildren in the tables are drawn in a color determined by their rating and activity. Namely, the activity determines the brightness of the color (from almost black to saturated), and the rating determines the shade (from purple through all the colors of the rainbow to red). For example, a student with a rating of 1 and activity of 10 will have a bright purple color, a student with a rating of 1 and activity of 0.1 will have a dark purple color, a student with a rating of about 100,000 and activity of 10 will have a bright green color, and with activity of 0.1 — dark green color; red color corresponds to a rating of 4500000.</p>
        
        <p>Specific formula: In the <a href="https://ru.wikipedia.org/wiki/HSV_(%D1%86%D0%B2%D0%B5%D1%82%D0%BE%D0%B2%D0%B0%D1%8F_%D0%BC%D0%BE%D0%B4%D0%B5%D0%BB%D1%8C)">HSV model</a>, the participant's color has the following components:</p>
        $h = k\cdot \log(r+r_0) + b$<br>
        $v = 0.3 + 0.7 \cdot \log(a+1) / \log(A + 1)$<br>
        $s = 1$<br>

    page(
        "About the \"Find a bug\" section", 
                                          String.raw"""<h1>About the "Find a bug" section</h1>
        <p>When you have solved a problem and received an "Accepted" for it, you have the opportunity to look for bugs in the submits of other students on this problem. Namely, a link "Find an bug" appears on the task page, which opens a list of specially selected incorrect solutions to this problem.
        (Of course, the link does not appear in every task, but only in those tasks where there are such specially selected solutions.)
        There is also a section in the site menu "<a href="/findMistakeList">Find a bug</a>", where there are links to all solutions in which you can look for errors
        (not all of these solutions are available to you — solutions are available to you only for those tasks for which you received a "Accepted").</p>

        <p>For each of the solutions in which you need to find an error, it is known that the error can be corrected by making no more than 15 edits in the solution code. An edit is considered to be adding, deleting, or changing one character (i.e., the <a href="/material/p1791">Levenshnein distance</a> is actually considered). Your task is to find the error, fix it, and get OK on the task. To give you some margin, you are allowed to make up to 23 edits.</p>

        <p>In the "Find a bug" interface, you are immediately given a text editor in which the solution code is open. I strongly recommend looking for errors directly in this editor, without copying the code anywhere (like your IDE or editor), and accordingly not using a debugger, etc., but only looking at the code with your eyes. But in the most difficult cases, you can copy the code and understand it more thoroughly.</p>

        <p>The solutions in the "Find a bug" section are available in different programming languages. Don't be afraid to look for bugs even in languages you don't know. I try not to allow those solutions in which the error is caused by language problems to search for errors, almost always errors have more algorithmic reasons, and, accordingly, you can find them, even if you do not know the features of the language.</p>

        <p>I do not look at the solutions sent through the "find a bug" section with my eyes and do not comment (in particular, it is impossible to get "accepted" for them), and they do not affect your results in the rankings. Of course, if you can't find an error, you can write to me, I will advise you something.</p>

        <p>Each solution, in addition to the problem, is also characterized by an individual number (a combination of four letters or numbers). Use this number to distinguish between solutions for finding errors for the same problem; in particular, if you want to ask me about such a solution, then specify both the name of the problem and the number of the solution (well, or just send a link to the error search page in this particular solution).</p>
        """, {id: "about_find_mistake"})

contacts = () ->
    label("""
