I am trying to get a total number of documents that have the mandatory records.

one document is defined by starting of INS segment until it encounters another one. Each document must have following records REF*0F, REF*23, DTP*356, DMG*D8 and should be in 1 to 1 ratio. The sequencing / ordering or records (REF*0F, REF*23, DTP*356, DMG*D8) can be random.

Pls help


file -

ISA*12345*
ABC**
INS*Y*19
REF*0F*
REF*1L*
REF*23*
DTP*356*
NM1*IL*
DMG*D8*
LUI*LE*
NM1*31*1
INS*Y*19
REF*0F*
REF*1L*
REF*23*
DTP*356*
NM1*IL*
DMG*D8*
LUI*LE*
NM1*31*1