How can I express the sentence: "Every human has exactly two legs" in First Order Logic

Question

How can I express the sentence: "Every human has exactly two legs" in First Order Logic without using the number 2 like the example "$(\forall x)(Human(x) \wedge NumberOfLegs(x, 2))$" and use something like $Leg(x,l)$ and $=$

Answer 1

$$\forall x\left[H\left(x\right)\to\exists u\exists v\left[u\neq v\wedge L\left(x,u\right)\wedge L\left(x,v\right)\wedge\forall z\left[L\left(x,z\right)\to\left(z=u\vee z=v\right)\right]\right]\right]$$ Here $H(x)$ stands for "$x$ is human" and $L(x,y)$ for "$y$ is a leg of $x$".

Answer 2

$$\forall x (H(x) \to \exists y \exists z (y \neq z \land \forall w(L(x,w) \leftrightarrow (w =y \lor w=z)))$$