### CONTEXT (Previous Events):
<system_output timestamp="823.350326"/>
<user_input timestamp="823.382964">[D</user_input>
<system_output timestamp="823.383352"/>
<user_input timestamp="823.418185">[D</user_input>
<system_output timestamp="823.418495"/>
<user_input timestamp="823.451267">[D</user_input>
<system_output timestamp="823.451549"/>
<user_input timestamp="823.482347">[D</user_input>
<system_output timestamp="823.482716"/>
<user_input timestamp="823.519079">[D</user_input>
<system_output timestamp="823.519338"/>
<user_input timestamp="823.552555">[D</user_input>
<system_output timestamp="823.552902"/>
<user_input timestamp="823.585435">[D</user_input>

### TARGET LINE (Extract and Classify THIS Timestamp):
<system_output timestamp="823.585711"/>

Answer: 823.585711, old event