Name of a film?!

The film is from the 60/70's and is more of a musical really!. Its very colourful and elaborate and its about a guy who starts at the bottom of a company and works his way up until he's almost the boss, and all this happens very quickly!. The guy who is in it has dark hair and at the end there is a big party on the buildings roof!. Thats all i remember from the film!.!.!.Www@Enter-QA@Com

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