x^12 , x^11 ,x^10
we want coeffient of x^10
which is sum of all possible combination 1*2+2*3+3*4+4*5 ....
-(sigma of i*j where i not equal to j from 1 to 12) since roots are all negative
sigma of (i(sigma (j)-i)/2 since every hetero combination is counted twice
so 1/2((n(n+1))^2/2^2-(2n+1)(n+1)(n)/6)
2717
