There are several benches with two seats and four seats in the venue. Students of a certain grade (less than 70 people) came to the meeting. Some students sat on a two-seat bench, and the rest sat on a four-seat bench. The result was an average of 1.35 seats per student. How many students are in the meeting?
会场里有两个座位和四个座位的长椅若干把．某年级学生(不足70人)来开会，一部分学生一人坐一把两座长椅，其余的人三人坐一把四座长椅，结果平均每个学生坐1.35个座位．问有多少学生参加开会？
<result>40</result>