M⁴n - m^5 - m^3 n² + m²n³ - mn⁴ + n^5

m⁴n - m^5 - m^3 n² + m²n³ - mn⁴ + n^5 = -m^5 - mn^4 - m^3n^2 + m^2n^3 + m^4n + n^5