Due to special reasons, only one audience came to Zhou Libo's performance. Fortunately, this audience invited 10 friends to watch together. But the number of people was still too small, so each of these audiences called 10 friends. Everyone saw that there were still too many empty seats, and everyone called 10 friends. Finally made this embarrassing talent show lively. How many spectators are there in total?
由于特殊原因，周立波的演出现场只来了一个观众，幸好这个观众又叫来了10个朋友一起观看．但人数还是太少，于是这些观众又每人叫来了10个朋友．大家一起看座位空下的还太多，又每个人叫来10个朋友．终于使这场尴尬的达人秀表演热闹了起来．现在现场一共有多少个观众．
<gadget id="calculator">1 + 10</gadget>
<output>11</output>

<gadget id="calculator">11 * 10</gadget>
<output>110</output>

<gadget id="calculator">110 + 11</gadget>
<output>121</output>

<gadget id="calculator">121 * 10</gadget>
<output>1_210</output>

<gadget id="calculator">1_210 + 121</gadget>
<output>1_331</output>

<result>1_331</result>