[Haskell-cafe] date parsing and formatting

I've been working with Haskell's Date.Time modules to parse a date like 12-4-1999 or 1-31-1999. I tried: parseDay :: String -> Day parseDay s = readTime defaultTimeLocale "%m%d%Y" s And I think it wants my months and days to have exactly two digits instead of 1 or 2... What's the proper way to do this? Also, I'd like to print out my Day in this format: 12/4/1999 what's the Haskell way to? Thanks for the help. Alex