Regular expression: how to capture word with only one repeated symbol

Regular expression: how to capture word with only one repeated symbol

Having an input of
aaadds bbbbb/bbbbb asdfdasf cccccccccc \n fffffff
what is the correct regex for getting 'cccccccccc' and 'fffffff'?
it should be something like [.]+ except for the fact that dot inside the
square brackets is literal and one can't simply backslash it.