[Haskell-cafe] Newb question about map and a list of lists

I have a list of lists of pairs of numeric Strings (like this: [["2","3"],["1","2"],["13","14"]] etc.) I'd like to change it into a list of a list of numbers, but I'm not sure how to go about it. If it was just one list, I could use map, but map.map doesn't seem to work. Any suggestions, or pointers to a reference online? thanks in advance, -- chuk