diff --git a/...essions/14-regexp-lookahead-lookbehind/1-find-non-negative-integers/solution.md b/...essions/14-regexp-lookahead-lookbehind/1-find-non-negative-integers/solution.md
@@ -1,9 +1,9 @@

-The regexp for an integer number is `pattern:\d+`.

-We can exclude negatives by prepending it with the negative lookbehind: `pattern:(?<!-)\d+`.

-Although, if we try it now, we may notice one more "extra" result:

```js run
let regexp = /(?<!-)\d+/g;
@@ -13,11 +13,11 @@ let str = "0 12 -5 123 -18";
console.log( str.match(regexp) ); // 0, 12, 123, *!*8*/!*
```

-As you can see, it matches `match:8`, from `subject:-18`. To exclude it, we need to ensure that the regexp starts matching a number not from the middle of another (non-matching) number.

-We can do it by specifying another negative lookbehind: `pattern:(?<!-)(?<!\d)\d+`. Now `pattern:(?<!\d)` ensures that a match does not start after another digit, just what we need.

-We can also join them into a single lookbehind here:

```js run
let regexp = /(?<![-\d])\d+/g;

diff --git a/9-regular-expressions/14-regexp-lookahead-lookbehind/2-insert-after-head/task.md b/9-regular-expressions/14-regexp-lookahead-lookbehind/2-insert-after-head/task.md
@@ -1,10 +1,10 @@
-# Insert After Head

-We have a string with an HTML Document.

-Write a regular expression that inserts `<h1>Hello</h1>` immediately after `<body>` tag. The tag may have attributes.

-For instance:

```js
let regexp = /your regular expression/;
@@ -20,7 +20,7 @@ let str = `
str = str.replace(regexp, `<h1>Hello</h1>`);
```

-After that the value of `str` should be:
```html
<html>
  <body style="height: 200px"><h1>Hello</h1>