It is known that a, b, c are positive integers, and a<b, a+b=52, ca=78. Find the maximum value of a+b+c.
已知a、b、c是正整数，且a＜b，a+b=52，c-a=78．求a+b+c的最大值．
<gadget id="calculator">52 / 2</gadget>
<output>26</output>

<gadget id="calculator">26 - 1</gadget>
<output>25</output>

<gadget id="calculator">52 + 78 + 25</gadget>
<output>155</output>

<result>155</result>