𝗙𝗶𝗹𝗹𝗼𝗺𝗶𝗻𝗼. Divide the grid into regions of orthogonally connected cells. Regions can be upto 9 cells large. Fill each region with the number of cells it contains (eg: fill any 7-cell regions with seven 7s, etc). 𝗔𝗻𝘁𝗶 𝗥𝗼𝘄/𝗖𝗼𝗹𝘂𝗺𝗻. Except for the given 1 in R3C1, the digit N cannot appear in row N or column N. 𝗚𝗲𝗿𝗺𝗮𝗻 𝗪𝗵𝗶𝘀𝗽𝗲𝗿𝘀. Orthogonally adjacent digits in different regions must differ by at least 5.