.net - Regex to exclude string at beginning of string -

i want exclude fixed string @ beginning, numbers after fixed string.

the fixed string re163, here examples expected result:

example     result re16310000  10000 re16312345  12345 re16316300  16300

i've tried following regex:

it works these examples:

re16310000  10000 re16319999  19999

but doesn't fit that:

re16320000  320000    (expected 20000) re16316320  320       (expected 16320)

why regex? substring enough:

string source = "re16310000";  string result = source.substring(5);

in case have use regular expressions can try

(?<=re163)[0-9]+$

pattern; c# example:

string pattern = @"(?<=re163)[0-9]+$";  string result = regex.match(source, pattern).value;

If cop