With three days until election day, both sides are throwing everything behind winning over those last few undecided voters in swing states.    Pennsylvania is one of the bigger prizes - Kamala Harris is scheduled to do five events in that state on Monday alone.   Sky News international affairs editor Dominic Waghorn is also there, speaking to one Republican couple with opposite views on Donald Trump.   And US correspondents James Matthews and Mark Stone discuss how important the economy will be when it comes to deciding who to vote for on Tuesday.  Producer: Rosie Gillott Assistant producer: Cailynn Birts Editor: Philly Beaumont