monocarp playing Minecraft want build wall cacti he want build field sand size n time m cell Initially cacti cell field Note Minecraft cacti grow cell adjacent initial field meet restriction Monocarp plant new cacti fulfil aforementione condition he can not chop cacti grow field do not axe cacti prickly handsMonocarp believe wall complete path row field row consecutive cell path adjacent cell belong path contain cactus your task plant minimum number cacti build wall report impossible