SQL & PL/SQL :: Error With Initially Deferred Deferrable Constraint

I am unable to add the rows even after using initially deferred deferrable constraint.

My Queries are as follows:-

SQL> create table chicken (cid int primary key,eid int);

Table created.

SQL> create table egg (eid int primary key,cid int);

Table created.

SQL> alter table egg add constraint eggREFchicken foreign key (cid) references chicken(cid) initially deferred deferrable;

Table altered.

SQL> alter table chicken add constraint chickenREFegg foreign key (eid) references egg(eid) initially deferred deferrable;

Table altered.

SQL> insert into egg values(1,2);
insert into egg values(1,2)
*
ERROR at line 1:
ORA-02291: integrity constraint (SCOTT.EGGREFCHICKEN) violated - parent key not found

why it is not inserting even after doing initially deferred deferrable. I am using SQL Plus to run Queries.