Why doesn't the regular expression for Java Pattern work correctly?

Question

Java

There is a regular expression

Pattern pattern = Pattern.compile("^(7)+(701|702|775|778|705|777|771|776|707|747|700|708)+(\\d{7})$");
        Matcher matcher = pattern.matcher(value);

those. according to my logic (probably I'm not thinking correctly),

the first occurrence of 7 is the first digit from the beginning of the string, then you need to find 1 from the list of prepared values, and after 7 any values.

In this case, the value: 77771234567 will work correctly, but if you add one more digit, then the value 7 (2nd character) will fall into group 1 and the second 771

i.e. it turns out that the 1st character is omitted, can someone explain how this can be fixed

Answer 1

The perks need to be removed. Because of them, the regex can consider the correct length of the string to be more than eleven characters.