Suppose Valentina is maximizing his utility from consuming milk and baby formula. The price of a 8oz bottle of milk is $40 and the price of a 8oz bottle of baby formula is $26. If the marginal utility of the last 8oz bottle of milk was 93 units, what was the marginal utility of the last 8oz bottle of baby formula she purchased? (hint: refer to the optimal choice condition for a well-behaved utility function)