Relevant departments have to continuously review 30 scientific research project plans. If the number of projects that are required to be reviewed every day is not equal to each other and is not zero, then the maximum number of projects that need to be reviewed.
有关部门要连续审核30个科研课题方案，如果要求每天安排审核的课题个数互不相等且不为零，则审核完这些课题最多需要多少．
<result>7</result>