Ubuntu 14.04 install gcc-4.5 and g++4.5

I'm trying to install gcc-4.5 and g++-4.5 on Ubuntu 14.04 sudo apt-get install gcc-4.5 g++-4.5 gcc-multilib g++-multilib but the following errors appeared:

Package gcc-4.5 is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourcePackage g++-4.5 is not available, but is referred to by another package.This may mean that the package is missing, has been obsoleted, oris only available from another sourceE: Package 'gcc-4.5' has no installation candidateE: Package 'g++-4.5' has no installation candidate

Can anyone tell me what I need to do?