B20=IF($A20<>"",SUM(IF(FREQUENCY(IF($D$3:$D$15<=$A20,IF($E$3:$E$15>=$A20,MATCH($B$3:$B$15&$C$3:$C$15,$B$3:$B$15&$C$3:$C$15,0))),ROW($B$3:$B$15)-ROW($B$3)+1),$C$3:$C$15)),"")

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