There are 156 students in the second grade of Hongri Primary School, 39 more than the third grade, and 78 more students in the fourth grade than the third grade. How many students are there in the fourth grade?
红日小学二年级有学生156人，比三年级多39人，四年级比三年级多78人，四年级有学生多少人？
<gadget id="calculator">156 - 39</gadget>
<output>117</output>

<gadget id="calculator">117 + 78</gadget>
<output>195</output>

<result>195</result>