Rman

Dear Friends,

I need to create a backup between to SCN (S)

there is a need to create backup between  SCN 3717460411 to 3717460822 any ideas?

whenever am trying my Rman command I am receveing this error

RMAN> BACKUP INCREMENTAL FROM SCN 3717460411 To SCN 3717460822 DATABASE FORMAT '/u01/database/ForStandby_%U' tag 'FORSTANDBY';

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-00558: error encountered while parsing input commands

RMAN-01009: syntax error: found "scn": expecting one of: "destination"

RMAN-01007: at line 2 column 43 file: standard input

thanks