how many rivers are in the state with the largest population
SELECT COUNT ( t2.river_name ) FROM river AS t2 JOIN state AS t1 ON t1.state_name  =  t2.traverse WHERE t1.state_name  =  ( SELECT state_name FROM state WHERE population  =  ( SELECT MAX ( population ) FROM state ) );
SELECT COUNT ( t2.river_name ) FROM river AS t2 JOIN state AS t1 ON t1.state_name  =  t2.traverse WHERE t1.state_name  =  ( SELECT state_name FROM state WHERE population  =  ( SELECT MAX ( population ) FROM state ) );
[{'COUNT ( t2.river_name )': 0}]