A battery of emf E0=12 V is connected across a 4m long uniform wire having resistance 4 Ω/m. The cells of small emfs ϵ1=2V and ϵ2=4V having internal resistance 2 Ω and 6 Ω respectively, are connected as shown in the figure. If galvanometer shows no deflection at the point N, the distance of point N from the point A is equal to