Not able to pass CLOB in Oracle function

I'm trying to pass CLOB as input parameter in oracle function. The function is created successfully, but when I try to pass a lengthy string, it gives

ora-01704 string literal too long

error.

Below is my function:

CREATE OR REPLACE FUNCTION mySchema.TESTFUNCTION(myData IN CLOB)
  RETURN INT
AS
BEGIN
  DBMS_OUTPUT.PUT_LINE(myData);
  RETURN 1;
END;

When I try to call this function by passing lengthy string more than 5000 characters, it gives the error.

Can anybody help please