Is the Following Bare Bones Program Self-Terminating? Explain Your Answer

Essay

Is the following Bare Bones program self-terminating? Explain your answer.
$\begin{array} { l } \text { copy } \mathrm { X } \text { to } \mathrm { Z } \\\text { decr } \mathrm { Z } \\\text { while } \mathrm { Z } \text { not } 0 : \\\text { decr } \mathrm { Z } \\\text { decr } \mathrm { X } \\\text { while } \mathrm { X } \text { not } 0 :\end{array}$