Exp_plan_interpret

Can anyone pleases let know how  to interpret the sql  explain plan?

for the id "0"  under "rows" ,"Bytes" and "TempSpc"  header,  its showing 189P and 15E hence please let know what does P and E stands for .

and how we  can further optimize

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| Id  | Operation                       | Name                      | Rows  | Bytes |TempSpc| Cost (%CPU)| Time     |

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|   0 | SELECT STATEMENT                |                           |   189P|    15E|       |    14T(100)|999:59:59 |

|   1 |  HASH GROUP BY                  |                           |   189P|    15E|    15E|    14T(100)|999:59:59 |

|*  2 |   HASH JOIN RIGHT OUTER         |                           |   189P|    15E|       |   547G(100)|999:59:59 |

|   3 |    VIEW                         | D_REV_TYPE            |  2737 |   406K|       |    18   (0)| 00:00:01 |

|   4 |     UNION-ALL                   |                           |       |       |       |            |          |

|   5 |      TABLE ACCESS FULL          | N_REVTYPE_DATA     |  2736 | 19152 |       |    16   (0)| 00:00:01 |

|   6 |      FAST DUAL                  |                           |     1 |       |       |     2   (0)| 00:00:01 |

|*  7 |    HASH JOIN RIGHT OUTER        |                           |  2625T|  1259P|       |  8166M (98)| 88:37:01 |

|   8 |     VIEW                        | D_REVENUE_TYPE            |  2737 |   545K|       |    18   (0)| 00:00:01 |

|   9 |      UNION-ALL                  |                           |       |       |       |            |          |