Instructions: Classify the given a piece of financial news into three classes: positive, negative, and neutral. Output must be 'positive', 'negative', or 'neutral'.
Input: Nyrstar has also agreed to supply to Talvivaara up to 150,000 tonnes of sulphuric acid per annum for use in Talvivaara 's leaching process during the period of supply of the zinc in concentrate .
Output:
positive