**Input:** $N$ ($N \ge 1$) qubits in the $|0 \dots 0\rangle$ state.

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

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