B'There are n cdot m unit cubes currently in positions (1, 1, 1) through (n, m, 1) . Each of these cubes is one of k colors. You want to add additional cubes at any integer coordinates such that the subset of cubes of each color is connected, where two cubes are considered connected if they share a face. In other words, for every pair of cubes of the same color c , it should be possible to travel from one to the other, moving only through cubes of color c that share a face. The existing cubes are currently in the corner of a room. There are colorless cubes completely filling the planes x = 0 , y = 0 , and z = 0 , preventing you from placing additional cubes there or at any negative coordinates. Find a solution that uses at most 4 cdot 10^5 additional cubes (not including the cubes that are currently present), or determine that there is no solution. It can be shown that under the given constraints, if there is a solution, there is one using at most 4 cdot 10^5 additional cubes. The first line of the input contains three integers n , m , and k ( 2 <= n, m, k <= 50 ) -- the number of rows and columns of cubes, and the number of colors, respectively. The i -th of the next n lines contains m integers. The j -th of these is a_{ij} ( 1 <= a_{ij} <= k ) -- the color of the cube at position (i, j, 1) . For every color from 1 to k , it is guaranteed that there is at least one cube in the input of that color. If there is no solution, print a single integer -1 . Otherwise, the first line of output should contain a single integer p ( 0 <= p <= 4 cdot 10^5 ) -- the number of additional cubes you will add. The next p lines should contain four integers x , y , z and c ( 1 <= x, y, z <= 10^6 , 1 <= c <= k ) -- indicating that you are adding a cube with color c at positi'...