Your challenge is to write a program which, given a year, outputs the number of "Friday 13ths" in it.
Rules & Details:
- You can take input via
STDIN, or as an argument passed to your program.
- You should output the result to
- You may assume that input will be a valid year, and does not pre-date the Gregorian calendar (undefined behaviour is permitted in these cases).
- Calendar/Date libraries are allowed.
This is a code-golf, so the shortest code (in bytes) wins.