Three blocks $A, B$ and $C$ are lying on a smooth horizontal surface, as shown in the figure. $A$ and $B$ have equal masses, $m$ while C has mass M . Block A is given an initial speed $v$ towards B due to which it collides with B perfectly inelastically. The combined mass collides with C , also perfectly inelastically $\frac{5}{6}$ th of the initial kinetic energy is lost in whole process. What is value of $M / m$ ?