(a + 1)(b + 1)(c + 1) = (ab + a + b + 1)(c + 1) = (abc + ab + ac + a + bc + b + c + 1) = abc + ab + ac + a + bc + b + c + 1
(a + 1)(b + 1)(c + 1) = (ab + a + b + 1)(c + 1) = (abc + ab + ac + a + bc + b + c + 1) = abc + ab + ac + a + bc + b + c + 1