What is the complement of exactly one?

Question

L = $\{\langle M \rangle \mid$ $M$ and $Y$ are TMs and $M(x) = Y(x)$ for exactly one $x \in \{1,2,\dots, k\}, k \in \mathbb N \}$

---

I want the complement for "$M(x) = Y(x)$ for exactly one $x \in \{1,2,\dots, k\}, k \in \mathbb N$" this part

Answer 1

The complement of exactly one is either none or more than one.