A polynomial $P(x)$ with real coefficients and of degree four satisfies the inequality
$$P(x) \geq x$$
for every real number $x$.
$$\begin{aligned}
& P(1) = 1 \\
& P(2) = 4 \\
& P(3) = 3
\end{aligned}$$
according to, $\mathbf{P(4)}$ is equal to what?