Please add a parenthesis in the formula 1+2*3+4*5+6 to make the number of the formula the largest, what is the largest number.
请你在算式1+2*3+4*5+6中添上一个小括号，使算式的得数最大，最大的得数是多少．
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">2 * 7 * 5</gadget>
<output>70</output>

<gadget id="calculator">1 + 70 + 6</gadget>
<output>77</output>

<result>77</result>