$Oil slid to a four-year low after #OPEC kept its oil production unchanged  http://stks.co/a1IX4 $USO $WTI $Brent
### Instruction: What is the sentiment of this news? Please choose an answer from {negative/neutral/positive}
### Input: $Oil slid to a four-year low after #OPEC kept its oil production unchanged  http://stks.co/a1IX4 $USO $WTI $Brent
### Response: negative