Two snails#642
A rectangular field consists of rows and columns. A snail has traversed this field in a clockwise spiral, starting from the upper left corner. Each cell is numbered consecutively in the order the snail visits it: 1, 2, 3, \ldots.
Now, a second snail appears at cell (i_1, j_1) and needs to reach cell (i_2, j_2). Each second, it may move to an adjacent cell (horizontally or vertically), but only if the number of the new cell differs from the previous cell by no more than .
Your task is to determine the minimum time required for the second snail to reach the target cell.
The input file contains integers , , , i_1, j_1, i_2, j_2 (1 \leq M, N \leq 10^{18}, 1 \leq k \leq 2 \cdot 10^{18}, 1 \leq i_1, i_2 \leq M, 1 \leq j_1, j_2 \leq N).
Output a single integer: the minimum time required for the second snail to reach the target cell.
Example 1