<s>[INST] Distinct natural numbers such that $ab=cd=a+b+c+d-3$ Find the distinct natural numbers $a,b​​,c,d$ who satisfying $ab=cd=a+b+c+d-3$.
 [/INST] Find natural numbers $(a,b)$ such that:  
$c$ = $\dfrac{1}{2}(a b-\sqrt{(a b-a-b+3)^2-4 a b)}-a-b+3 )$
and $d$ = $\dfrac{1}{2}$ $(a b+\sqrt{(a b-a-b+3)^2-4 a b)}-a-b+3)$  
are natural numbers.  
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