Uninstalling Mariadb and installing MySQL

I had MariaDB installed on Ubuntu 16.04. Then tried to replace it with MySQL. After un-installing MariaDB now MySQL won't be install and I receive this error:

Errors were encountered while processing:
 mysql-server-5.7
E: Sub-process /usr/bin/dpkg returned an error code (1)

I also run rm /etc/mysql /var/lib/mysql -r to delete configuration files, but no chance.