**Input:** $N$ ($N \ge 1$) qubits in the $\ket{0 \dots 0}$ state.

**Goal:**  Change the state of the qubits to an equal superposition of all basis vectors $\frac{1}{\sqrt{2^N}} \big (\ket{0 \dots 0} + \dots + \ket{1 \dots 1}\big)$. 

> For example, for $N = 2$ the final state should be  $\frac{1}{2} \big (\ket{00} + \ket{01} + \ket{10} + \ket{11}\big)$.