Design an FSA that will recognize date expressions that come in two forms: $19/1/2021($the day is first$)$ or $19$ Jan $2021.$ Assume that date strings are fed to your FSA one character at a time. In general, assume the patterns are either DD$/$MM$/$YYYY or $"$DD MMM YYYY$",$ where MM $=$ a one$-$ or two$-$digit month string, between $1$ and $12$ inclusive; DD $=$ a one$-$ or two$-$digit day string, between $1$ and $31$ inclusive; and YYYY $=$ a one$-$to$-$four$-$digit year string, between $0$ and $9999$ inclusive; and MMM $=$ a three character month string, starting with a capital letter, one of Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, or Dec. In the first pattern, there will be no whitespace; in the second pattern, assume that the day$/$month and month$/$year strings are separated by a single space.

Write your solution to above given problem as a regular expression. You may split the regular expression in parts if you so wish.