B"The world is a grid with n rows and m columns. The rows are numbered 0, 1, ldots, n-1 , while the columns are numbered 0, 1, ldots, m-1 . In this world, the columns are cyclic (i.e. the top and the bottom cells in each column are adjacent). The cell on the i -th row and the j -th column ( 0 <= i < n, 0 <= j < m ) is denoted as (i,j) . At time 0 , the cell (i,j) (where 0 <= i < n, 0 <= j < m ) contains either a rock or nothing. The state of cell (i,j) can be described using the integer a_{i,j} : As a result of aftershocks from the earthquake, the columns follow tectonic plate movements: each column moves cyclically upwards at a velocity of 1 cell per unit of time. Formally, for some 0 <= i < n, 0 <= j < m , if (i,j) contains a rock at the moment, it will move from (i, j) to (i - 1, j) (or to (n - 1, j) if i=0 ). The robot called RT is initially positioned at (0,0) . It has to go to (n-1,m-1) to carry out an earthquake rescue operation (to the bottom rightmost cell). The earthquake doesn't change the position of the robot, they only change the position of rocks in the world. Let RT's current position be (x,y) ( 0 <= x < n, 0 <= y < m ), it can perform the following operations: Note that RT cannot go left using the operations nor can he stay at a position. Unfortunately, RT will explode upon colliding with a rock. As such, when RT is at (x,y) and there is a rock at ((x+1) bmod n, y) or ((x+2) bmod n, y) , RT cannot move down or it will be hit by the rock. Similarly, if y+1 < m and there is a rock at ((x+1) bmod n, y+1) , RT cannot move right or it will be hit by the rock. However, it is worth noting that if there is a rock at (x bmod n, y+1) and ((x+1) bmod n, y) , RT can still move right safely. Find the minimum amount of time RT needs to reach (n-1,m-1) without colli"...