Muskan is making a fruit salad with the following quantities:
- \( \frac{m + n}{m^2 + mn + n^2} \) cup of strawberries.
- \( \frac{m - n}{m^2 - mn + n^2} \) cup of another fruit (not specified).
These expressions represent the amounts of strawberries and another fruit in the fruit salad, respectively. The quantities are given in terms of the variables \( m \) and \( n \).