What is the minimum cost of crashing the following project at Sawaya Robotics by $4$ days?

$\backslash$table$[[$ACTIVITY$,\backslash$table$[[$NORMAL$],[$TIME $($DAYS$)]],\backslash$table$[[$CRASH$],[$TIME $($DAYS$)]],\backslash$table$[[$NORMAL$],[$COST$]],\backslash$table$[[$CRASH$],[$COST$]],$IMMEDIATE PREDECESSOR$($S$)],[$Design $($A$),6,5,900,1,000,-],[$Wiring $($B$),8,6,300,400,-],[$Chip install $($C$),4,3,500,600,$A$],[$Software $($D$),5,3,900,1,200,$A$,$ B$],[$Testing $($E$),8,5,1,000,1,600,$C$]]$

he minimum cost of crashing the following project at Sawaya Robotics by$.4$ days is $ $($enter your response as a whole number$).$