         
         <h2>Materials</h2>
         
-        <p>If you do not need the functionality of the algprog, but only <i>materials</i> — theoretical materials, video lectures, tasks, etc. — then they are freely available in one form or another. Theoretical materials, the author of which I am, as a rule, are distributed under one or another free license, you can use them. It is usually indicated in the material itself, if the license is not specified there, then ask me. The materials that I am not the author of are taken from other sites, you can usually use them too. Almost all tasks are taken from public sites <a href="https://informatics.mccme.ru">informatics.mccme.ru</a> and <a href="https://codeforces.com">codeforces.com</a> on both of these sites, you can form your courses from the tasks available there, etc. (in particular, computer science is specially made for conducting various courses). Basic (although already outdated) the contents of the algoprog are on informatics: <a href="https://informatics.msk.ru/course/view.php?id=1135">informatics.msk.ru/course/view.php?id=1135</a> — actually, the whole algoprog grew out of my computer science course.</p>
+        <p>If you do not need the functionality of the algprog, but only <i>materials</i> — theoretical materials, video lectures, tasks, etc. — then they are freely available in one form or another. Theoretical materials, the author of which I am, as a rule, are distributed under one or another free license, you can use them. It is usually indicated in the material itself, if the license is not specified there, then ask me. The materials that I am not the author of are taken from other sites, you can usually use them too. Almost all tasks are taken from public sites <a href="https://informatics.msk.ru">informatics.msk.ru</a> and <a href="https://codeforces.com">codeforces.com</a>, on both of these sites you can form your courses from the tasks available there, etc. Basic (although already outdated) contents of the algoprog are on informatics: <a href="https://informatics.msk.ru/course/view.php?id=1135">informatics.msk.ru/course/view.php?id=1135</a> — actually, the whole algoprog grew out of my informatics course.</p>
         
         <h2>Engine</h2>
         
-        <p>The algoprog engine itself is also <a href="https://github.com/petr-kalinin/algoprog">freely available</a>, you can raise your own instance of algoprog and do anything there. (Although, of course, it's not that easy, and I'm unlikely to help you.)</p>
+        <p>The algoprog engine itself is also <a href="https://github.com/petr-kalinin/algoprog">freely available</a>, you can set up your own instance of algoprog and do anything there. (Although, of course, it's not that easy, and I'm unlikely to help you.)</p>
         
         <h2>A separate instance</h2>
         
-        <p>I can raise a separate instance of the algoprog for your students, with your materials and tasks. This requires a separate discussion, but in principle it is possible. It will be paid, the specific cost will depend on the necessary work to support the instance, the necessary improvements, and the expected number of students. As a rough preliminary assessment, if no serious improvements are required, and 20-50 students are expected, then the cost of a separate instance will be about 1000 rubles per student per month; if there are fewer students, then the cost, of course, will be higher.</p>
+        <p>I can set up a separate instance of the algoprog for your students, with your materials and tasks. This requires a separate discussion, but in principle it is possible. The cost will depend on the necessary work to support the instance, the necessary improvements, and the expected number of students. As a rough preliminary assessment, if no serious improvements are required, and 20-50 students are expected, then the cost of a separate instance will be about 1000 rubles per student per month; if there are fewer students, then the cost, of course, will be higher.</p>
         
         <h2>Classes directly on the algoprog based on the materials of the algoprog</h2>
         
-        <p>If you want to do it on the algoprog, then there are the following options. Firstly, your students can register on the algoproge and study as independent students. From my point of view, these will be just additional students on the algoproge, you will be able to organize classes, help students, etc., but you will not have any additional opportunities on the algoproge (you will not be able to view student decisions, etc.). Your students are engaged independently, for them the cost of classes will, of course, be determined <a href="/pay">by the general rules</a>, of course, I will not take money from you (and in general I may not know about you :)).</p>
-        
-        <p>If you want to have additional opportunities — to view students' decisions, comment on them, count/ignore them, have separate summary tables, then write to me. All of this (as well as other requests from your side) is quite realistic, but requires a separate discussion. As <b>basic</b> options , there are the following:</p>
-        <ul>
-        <li>Your students are engaged in the algoproge on an equal footing with the rest, I check them, comment on them, count/ignore their decisions — and plus you can do the same; there will be separate signs for your students, etc.<b>As a rule</b>, the cost of such classes for your students will be the same as if they were engaged independently. (That is, there is no additional payment for additional functionality, but there are no discounts either.)</li>
-        <li>I don't interact with your students in any way — I don't look at their decisions, I don't count/ignore them. You do all this, if you want.<b>As a rule</b>, the cost of such classes for your students will be two times less than if they were engaged independently.</li>
+        <p>If you want to do it on the algoprog, then there are the following options. Firstly, your students can register on the algoproge and study as independent students. From my point of view, these will be just additional students on the algoprog, you will be able to organize classes, help students, etc., but you will not have any additional rights on the algoprog itself (you will not be able to view student submissions, etc.). Your students are engaged independently, for them the cost of classes will, of course, be determined <a href="/pay">by the general rules</a>, of course, I will not take money from you (and in general I may not know about you at all :)).</p>
+        
+        <p>If you want to have additional features — to view students' submissions, comment on them, accept/ignore them, have separate summary tables, then contact me. All of this (as well as other requests from your side) is quite realistic, but requires a separate discussion. As <b>basic</b> options , there are the following:</p>
+        <ul>
+        <li>Your students are studying in the algoprog on an equal footing with the rest, I check their submissions, comment on them, accept/ignore — and plus you can do the same; there will be separate rankings for your students, etc.<b>As a rule</b>, the cost of such classes for your students will be the same as if they were studying independently. (That is, there is no additional payment for additional functionality, but there are no discounts either.)</li>
+        <li>I don't interact with your students in any way — I don't look at their code, I don't accept/ignore them. You do all this, if you want.<b>As a rule</b>, the cost of such classes for your students will be two times less than if they were engaged independently.</li>
         </ul>
         <p>In both variants above, the words "basic" (variants) and "as a rule" are essential. This means that, on the one hand, this is not a public offer — in a particular situation, other conditions and other prices are possible; on the other hand, other options are also possible in terms of functionality and in our interaction with you. Write, let's talk :)</p>
-        
-        <p>In particular, if algoprog classes would be free for your students if they were engaged in algoprog themselves, then both options above will be, as a rule, free.</p>
         
         </div>""")
 

    page(
        "About the \"Find a bug\" section", 
                                          String.raw"""<h1>About the "Find a bug" section</h1>
        <p>When you have passed the solution to the problem and received an "Accepted" for it, you have the opportunity to look for bugs in the decisions 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 the 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>About 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. Even with a margin, you are given the opportunity to make up to 23 edits.</p>

        <p>In the error search 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 to yourself (to 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 to yourself 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 general table. 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>

        <p>So far, in principle, there are not very many solutions in which to look for errors; over time, I think there will be more of them.</p>""", {id: "about_find_mistake"})

contacts = () ->
    label("""

        
        <p>When displaying the rating in tables, it is rounded to integers, but when calculating everything is considered real numbers.</p>
        
        <p>Cost table (rounded to two decimal places):</p>
        <pre>          A            B        C         D
         1       2.50       3.14       3.95       4.97
         2       6.25       7.86       9.88
         3      15.62      19.65      24.71      31.07
