clear @s paper{stats_paper:1}
kill @e[nbt={Item:{tag:{stats_paper:1}}}]

# slot filled with not paper
execute if predicate items:35th/filled unless predicate items:35th/stats_paper run tellraw @s ["",{"text":"[!] ","color":"red","bold":true},{"translate":"msg.stats_paper_slot","color":"gray","bold":false}]

# slot empty
execute unless predicate items:35th/filled run function items:stats_calc/paper/lore
