i need help to write the following in python.

Write a program to read dates from input, one date per line. Each date's format must be as follows: March 1, 1990. Any date not following that format is incorrect and should be ignored. The input ends with -1 on a line alone. Output each correct date as: 3/1/1990.

Hint: Use string[start:end] to get a substring when parsing the string and extracting the date. Use the split() method to break the input into tokens.

Ex: If the input is:

March 1, 1990 April 2 1995 7/15/20 December 13, 2003 -1

then the output is:

3/1/1990 12/13/2003