Activities $A,B,C,$ and $D,$ with durations $7,12,9,$ and $6$ respectively, are all connected with start$-$to$-$start relationships. There are $2$ days of lag from B to $C$ and $1$ day from $C$ to D$.$ Develop the network diagram and calculate the CPM values, show them on the diagram, and indicate all critical activities. Also, indicate the project duration.

Activities A$,$ B$,$ E$,$ and F$,$ with durations $2,7,10,$ and $3$ respectively, are all connected with finish$-$to$-$finish relationships. There are $4$ days of lag from $A$ to $B$ and $1$ day from $E$ to F$.$ Develop the network diagram and calculate the CPM values, show them on the diagram, and indicate all critical activities. Also, indicate the project duration.