shing on a project network for a large computer installation $($all are, of course, critical$).$ Activity details are in the following table:

$\backslash$table$[[$Activity$,\backslash$table$[[$Normal$],[$Time $($days$)]],\backslash$table$[[$Crash$],[$Time $($days$)]],\backslash$table$[[$Normal$],[$Cost$]],\backslash$table$[[$Total Cost$],[$with$],[$Crashing$]],$Immediate Predecessor$($s$)],[$A$,7,6,$$$5,000,$$$5,600,],[$B$,4,2,$$$1,200,$$$3,000,$A$],[$c$,11,9,$$$4,200,$$$6,200,$B$]]$

to reduce the project duration by $1$ day is $A$

to reduce the project duration by one additional day is $B$

$2$ days $=$$$2400.($Enter your response as an integer.$)$