There is a class of natural numbers, they are all square numbers, and the last three digits are the same, for example: 45**2=2025, 55**2=3025, 95**2=9025, their last three digits are the same as "025 ", what is the smallest of these natural numbers?
有一类自然数，它们都是平方数，且最后三位数字相同，例如：45**2=2025，55**2=3025，95**2=9025它们的后三位数相同都是"025"，这类自然数中最小的是多少？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<result>100</result>