Xiao Li originally planned to write 15 brush characters a day, but actually wrote 5 more a day, and ended up completing the scheduled task 2 days ahead of schedule. How many brush characters did Xiao Li originally plan to write?
小李原计划每天写15个毛笔字，实际每天多写了5个，结果提前2天完成预定任务．小李原计划写多少个毛笔字？
<result>20</result>