proc j_get_route_length { j_args } {
	set j_route_length 0
	if { [get_attr [get_nets $j_args ] route_length ] == 0 } { return 0 } 
	foreach obj [get_attr [get_nets $j_args ] route_length ] {
		set j_route_length [expr $j_route_length + [lindex $obj 1 ] ]
	}
	return $j_route_length
}

foreach_in_collection j_obj [get_nets -hier ] {
	set j_net_name [get_attr $j_obj full_name ] 
	set j_net_length [ j_get_route_length $j_net_name ]
	if { $j_net_length > 300 } {
		puts $j_net_name
	}
}