"BBB"
"AB"
"AAA"
"AB"
"BBB"
"AAA"
"AB"
"AA"
"B"
"BBB"
"AAA"
"AA"
"AB"
"B"
"BBB"
"AAA"
"AA"
"AB"
"B"
"AAA"
"B"
"CB"
"AC"
"CB"
"AC"
"BBB"
"AAA"
"AA"
missing data
"AAA"
"B"
"CB"
"AC"
"CB"
"AC"
"BBB"
"AAA"
"AA"
missing data