conversations.from: human
conversations.value: John goes to the market and buys 3 goats for $500 each and 2 cows for $1500 each.  How much money did he spend?
conversations.from: assistant
conversations.value: The goats cost 3*500=$1500
  The cows cost 2*1500=$3000
  So in total he spends 1500+3000=$4500