input-file.csv

GRU,BRC,10
BRC,SCL,5
GRU,CDG,30
GRU,SCL,20
GRU,ORL,56
ORL,CDG,5
SCL,ORL,20
GRU,CDG,35
DDD-RRR1
DDD-RRR2
DDD-RRR3
DDD-RRR3
DDD-RRR3
DDD-RRR3