If you are not the person who wrote this INDEX(Sheet2!A:A,small(IF("N"=INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&3):INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&19),ROW(INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&3):INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&19))-ROW(INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&3):INDIRECT("Sheet2!"&INDEX(Sheet1!B:B,MATCH(MATCH(Sheet3!A2,Sheet2!1:1,0)+3,Sheet1!A:A,0))&19),1,1)+1),1)) then dont think you can fix it. route it to him who wrote it.
Solved by F. F. in 28 mins