I am using Firefox 11.0 in Ubuntu 12.04 64 bit OS and trying to play YouTube video and it asks to install Adobe Flash player. But when I try to install through the Ubuntu software centre but I cannot find in the list by typing Flash or Adobe. I even tried the following command:
sudo apt-get install adobe-flashplugin
but it says that the package is missing or obsolete
sudo apt-get install ubuntu-restricted-extras
but still it says that the packages were automatically installed and no longer required.