How to figure "Date Acquired" and "Cost Basis" on stock that "Spun Off" shares before undergoing a reverse split? Fractional shares received were liquidated. 1099-B

DWDP spun off shares of DOW on 4/2/2019 and shares of CTVA on 6/3/2019 before undergoing a reverse split to shares of DD on 6/3/2019. DWDP shareholders received 1 share of DOW, CTVA, and DD for every 3 shares of DWDP held at the time of each corparate action's record date. Any fractional shares of DOW, CTVA, or DD received as a result of these transactions were liquidated. Mine were liquidated.