Is there an opening act? There probably is. That will last about 1 hour. Then there will be a 30-45 minute break to reset the stage, and then the headliner will be 1-1/2 to 2 hours - which will include an intermission.
It will probably end late, before you have Pink (or the main event), you will probably have "sponsor" bands to get the crowd going. Maybe an hour for each band- Pink will be the last one to perform. :) I hope this helps, and I hope you have fun :D