student adds consecutive natural numbers 1, 2, 3, 4... one by one until a certain natural number. Due to the omission of a natural number in the calculation, the wrong sum is 2011. What is the omission of a natural number?
某学生将连续自然数1、2、3、4…逐个相加直到某自然数为止．由于计算漏加了一个自然数而出了错误的和为2011，这个漏加的自然数是多少．
<gadget id="calculator">2_016 - 2_011</gadget>
<output>5</output>

<result>5</result>