Ex5 14

$\def\abs#1{|#1|}\def\i{\mathbf {i}}\def\ket#1{|{#1}\rangle}\def\bra#1{\langle{#1}|}\def\braket#1#2{\langle{#1}|{#2}\rangle}\def\tr{\mathord{\mbox{tr}}}\mathbf{Exercise\ 5.14}$

Show how to implment the Toffoli gate $\bigwedge_2 X$ in terms of single-qubit and $C_{not}$ gates.