How can I solve the following problem:

$f, \pi, g$ accept one, two and three arguments respectively. If you know that $f, \pi, g$ are primitive recursive functions prove that $h$ defined as:

$\begin{array}{lcl} h(0, y) \simeq f(y) \newline h(x + 1, y) \simeq g(x, y, h(x, \pi(x, y))) \end{array}$ is also primitive recursive function.