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how to extract some terms out from an expression



I have an expression as below：



$-\frac{1}{2} A[a,v] A[b,h] A[c,v] A[d,h] \text{Cos}[\theta ]^2+\frac{1}{2} A[a,h] A[b,v] A[c,v] A[d,h] \text{Cos}[\theta ]^2+\frac{1}{2} A[a,v] A[b,h] A[c,h] A[d,v] \text{Cos}[\theta ]^2-\frac{1}{2} A[a,h] A[b,v] A[c,h] A[d,v] \text{Cos}[\theta ]^2+\frac{1}{2} A[a,v]^2 A[b,h] A[d,h] \text{Cos}[\theta ] \text{Sin}[\theta ]-\frac{1}{2} A[a,h] A[a,v] A[b,v] A[d,h] \text{Cos}[\theta ] \text{Sin}[\theta ]+\frac{1}{2} A[b,v] A[c,h] A[c,v] A[d,h] \text{Cos}[\theta ] \text{Sin}[\theta ]-\frac{1}{2} A[b,h] A[c,v]^2 A[d,h] \text{Cos}[\theta ] \text{Sin}[\theta ]-\frac{1}{2} A[a,h] A[a,v] A[b,h] A[d,v] \text{Cos}[\theta ] \text{Sin}[\theta ]+\frac{1}{2} A[a,h]^2 A[b,v] A[d,v] \text{Cos}[\theta ] \text{Sin}[\theta ]-\frac{1}{2} A[b,v] A[c,h]^2 A[d,v] \text{Cos}[\theta ] \text{Sin}[\theta ]+\frac{1}{2} A[b,h] A[c,h] A[c,v] A[d,v] \text{Cos}[\theta ] \text{Sin}[\theta ]-\frac{1}{2} A[a,v] A[b,v] A[c,h] A[d,h] \text{Sin}[\theta ]^2+\frac{1}{2} A[a,v] A[b,h] A[c,v] A[d,h] \text{Sin}[\theta ]^2+\frac{1}{2} A[a,h] A[b,v] A[c,h] A[d,v] \text{Sin}[\theta ]^2-\frac{1}{2} A[a,h] A[b,h] A[c,v] A[d,v] \text{Sin}[\theta ]^2$



There are 16 terms here and every term has for function $A$.


In some terms the first parameter of four function $A$ are different from each other( a,b,c,d), in the other terms the four first paramenter are partial overlap(a,a,b,d;...).


how can I get the first kind. (the result is as below:)



$-\frac{1}{2} A[a,v] A[b,h] A[c,v] A[d,h] \text{Cos}[\theta ]^2+\frac{1}{2} A[a,h] A[b,v] A[c,v] A[d,h] \text{Cos}[\theta ]^2+\frac{1}{2} A[a,v] A[b,h] A[c,h] A[d,v] \text{Cos}[\theta ]^2-\frac{1}{2} A[a,h] A[b,v] A[c,h] A[d,v] \text{Cos}[\theta ]^2-\frac{1}{2} A[a,v] A[b,v] A[c,h] A[d,h] \text{Sin}[\theta ]^2+\frac{1}{2} A[a,v] A[b,h] A[c,v] A[d,h] \text{Sin}[\theta ]^2+\frac{1}{2} A[a,h] A[b,v] A[c,h] A[d,v] \text{Sin}[\theta ]^2-\frac{1}{2} A[a,h] A[b,h] A[c,v] A[d,v] \text{Sin}[\theta ]^2$




this is the input form for our mma:


 -(1/2) A[a, v] A[b, h] A[c, v] A[d, h] Cos[\[Theta]]^2 + 
 1/2 A[a, h] A[b, v] A[c, v] A[d, h] Cos[\[Theta]]^2 + 
 1/2 A[a, v] A[b, h] A[c, h] A[d, v] Cos[\[Theta]]^2 - 
 1/2 A[a, h] A[b, v] A[c, h] A[d, v] Cos[\[Theta]]^2 + 
 1/2 A[a, v]^2 A[b, h] A[d, h] Cos[\[Theta]] Sin[\[Theta]] - 
 1/2 A[a, h] A[a, v] A[b, v] A[d, h] Cos[\[Theta]] Sin[\[Theta]] + 
 1/2 A[b, v] A[c, h] A[c, v] A[d, h] Cos[\[Theta]] Sin[\[Theta]] - 
 1/2 A[b, h] A[c, v]^2 A[d, h] Cos[\[Theta]] Sin[\[Theta]] - 
 1/2 A[a, h] A[a, v] A[b, h] A[d, v] Cos[\[Theta]] Sin[\[Theta]] + 

 1/2 A[a, h]^2 A[b, v] A[d, v] Cos[\[Theta]] Sin[\[Theta]] - 
 1/2 A[b, v] A[c, h]^2 A[d, v] Cos[\[Theta]] Sin[\[Theta]] + 
 1/2 A[b, h] A[c, h] A[c, v] A[d, v] Cos[\[Theta]] Sin[\[Theta]] - 
 1/2 A[a, v] A[b, v] A[c, h] A[d, h] Sin[\[Theta]]^2 + 
 1/2 A[a, v] A[b, h] A[c, v] A[d, h] Sin[\[Theta]]^2 + 
 1/2 A[a, h] A[b, v] A[c, h] A[d, v] Sin[\[Theta]]^2 - 
 1/2 A[a, h] A[b, h] A[c, v] A[d, v] Sin[\[Theta]]^2


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