In the seventh grade, two dormitories for boys and girls were rated as "excellent dormitories" by the school. The grade group purchased a batch of diaries to reward them. If each person in the boys' dormitory is awarded 3 and each in the girls' dormitory is awarded 4, there will be an extra 8 If each person in the boys' dormitory is awarded 3, and each in the girls' dormitory is awarded 5, then there are 7 less. It is known that the number of boys in the boys' dormitory is 1 more than the number of girls in the girls' dormitory. How many diaries did the grade group buy?
七年级有男、女两间寝室被评为学校"优秀寝室"，年级组购置了一批日记本奖励他们，如果男生寝室每人奖3个，女生寝室每人奖4个，则多出8个；如果男生寝室每人奖3个，女生寝室每人奖5个，则少7个，已知男生寝室人数比女生寝室人数多1人，那么年级组购置了多少个日记本？
<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">3 + 8 + 3</gadget>
<output>14</output>

<gadget id="calculator">5 - 3 - 4</gadget>
<output>-2</output>

<gadget id="calculator">4 + (-2)</gadget>
<output>2</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<gadget id="calculator">7 + 1</gadget>
<output>8</output>

<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<gadget id="calculator">24 + 28 + 8</gadget>
<output>60</output>

<result>60</result>