[['serial & branch', 'seaman', 'mechanical', 'secretariat', 'supply', 'electrical', 'radio electrical', 'regulating', 'medical'], ['1', 'od ( ordinary seaman )', 'me ii', 'wtr ii', 'sa ii', 'en ii', 'ren ii', 'pm ii', 'ma ii'], ['2', 'ab ( able seaman )', 'me i', 'wtr i', 'sa i', 'en i', 'ren i', 'pm i', 'ma i'], ['3', 'ls ( leading seaman )', 'lme', 'lwtr', 'lsa', 'len', 'lren', 'lpm', 'lma'], ['4', 'po ( petty officer )', 'era - iv', 'po (w)', 'po (s)', 'ea - iv', 'rea - iv', 'po (r)', 'po (med)'], ['5', 'cpo ( chief petty officer )', 'era - i / ii / iii', 'cpo (w)', 'cpo (s)', 'ea - i / ii / iii', 'rea - i / ii / iii', 'cpo (reg)', 'cpo (med)'], ['6', 'scpo ( senior chief petty officer )', 'scpo (e) , cera', 'scpo (w)', 'scpo (s)', 'scpo (l) , cea', 'scpo (r) , crea', 'scpo (reg)', 'scpo (med)'], ['7', 'mcpo ( master chief petty officer )', 'mcpo (e)', 'mcpo (s)', 'mcpo (s)', 'mcpo (l)', 'mcpo (r)', 'mcpo (reg)', 'mcpo (med)'], ['8', 'honorary sub lieutenant (x)', 'hon s lt (e)', 'hon s lt (s)', 'hon s lt (s)', 'hon s lt (l)', 'hon s lt (r)', 'hon s lt (reg)', 'hon s lt (w / m)']]
the Seaman is Po when the Mechanical is Era - Iv
the [ENT] is [ENT] when the [ENT] is [ENT]