Three Blocks

Three identical blocks of mass $m$ are connected by springs as shown. The springs have un-stretched length $L_0$ and force constant $k$ .

Initially, the three blocks are aligned vertically, and the springs are un-stretched. The middle block (Block 2) has a horizontal speed $v_0$ and zero vertical speed. The other two blocks (Blocks 1 and 3) are initially at rest.

How far from its starting position is Block 2 when Blocks 1 and 3 collide?

Details and Assumptions:
1) There is no gravity, and the blocks have zero size
2) $m = L_0 = v_0 = 1$
3) $k = 10$