For certain real values of \(a, b, c,\) and \(d_{},\) the equation \(x^4+ax^3+bx^2+cx+d=0\) has four non-real roots. The product of two of these roots is \(13+i\) and the sum of the other two roots is \(3+4i,\) where \(i=\sqrt{-1}.\) Find \(b.\)

(第十三届AIME1995 第5题)