If ` A = 1/1 cot ^(-1) (1/1) + 1/2 cot^(-1) (1/2) + 1/3 cot ^(-1) ( 1/3) " and " `B = 1 `cot^(-1) ( 1)` + `2 cot^(-1) (2)` + `3 cot^(-1) (3)` " then " |B - A| " is equal to " (a`pi`)/b + c/d `cot ^(-1) (3)` `
where `a,b,c,d in N ` are in their `lowest form , find ` ( b -a - c - d) `

Answer

8