Question: I never wrote any complex regular expression before, and what I need seems to be (at least) a bit complicated.

I need a Regex to find matches for the following:

```
"On Fri, Jan 16, 2015 at 4:39 PM"

```

Where `On` will always be there;

then 3 characters for week day;

`,` is always there;

space is always there;

then 3 characters for month name;

space is always there;

day of month (one or two numbers);

`,` is always there;

space is always there;

4 numbers for year;

space `at` space always there;

time (have to match `4:39` as well as `10:39`);

space and 2 caps letters for `AM` or `PM`.

Answer: 
```
/On \w{3}, \w{3} \d{1,2}, \d{4} at \d{1,2}:\d{1,2} [A-Z]{2}/

# \w{3} for 3 charecters
# \d{1,2} for a or 2 digits
# \d{4} for 4 digits
# [A-Z]{2} for 2 capital leters

```
/On [A-Za-z]{3}, [A-Za-z]{3} \d{1,2}, \d{4} at \d{1,2}:\d{1,2}/g