If `alpha,beta; beta,gamma; gamma,alpha` are the roots of `a_i x^2 + b_i x + c_i = 0`, for i = 1,2,3,(given that `alpha,beta,gamma >0`) if `sum alpha + sum alpha beta + alpha beta gamma = (Pi_(i=1)^3 ((a_i - b_i + c_i)/(a_i))^(1/2)` + k, then k is equal to