@technocrat after giving the command r version is remaining same
Reading package lists... Done
Building dependency tree
Reading state information... Done
r-base is already the newest version (3.6.3-2).
r-base-dev is already the newest version (3.6.3-2).
r-base-dev set to manually installed.
0 upgraded, 0 newly installed, 0 to remove and 229 not upgraded.