In a box of chocolates, if you count 7 pieces, you still have 5 pieces, and if you count 9 pieces, you still have 2 pieces left. How many pieces of chocolate are there at least in this box?
一盒巧克力，7粒一数还余5粒，9粒一数又少2粒．这盒巧克力至少有多少粒？
<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<gadget id="calculator">63 - 2</gadget>
<output>61</output>

<result>61</result>