forward 5
down 5
forward 8
up 3
down 8
forward 2

BEGIN { FS=" " }
/forward/ { h_pos += $2 }
/down/    { depth += $2 }
/up/      { depth -= $2 }
END { print depth * h_pos }

BEGIN { FS=" " }
/down/    { aim += $2 }
/up/      { aim -= $2 }
/forward/ { 
	h_pos += $2
	depth += aim * $2
}
END { print depth * h_pos }