Error in getting top 10 biggest table

Hi  , 

I am executing below query to get top 10 biggest size table but getting error

SELECT table_name,pg_relation_size(table_schema || '.' || table_name) as size FROM information_schema.tables WHERE table_schema NOT IN ('information_schema', 'pg_catalog') ORDER BY size DESC LIMIT 10;

It seems problem is with CAPS letter in Postgres table .

So any possibilities to execute this Caps letter table without any error