On an (n+2)-bit quantum network, a gate for conditional NOT operation with n≧5 bits of controls (a C^nNOT gate) can be simulated with 24n-64 gate of conditional two-bit operations, as well as with 32n-4 gates of CNOT and one-bit operations. These small numbers of elementary gates (which are approximately half or two thirds of the number known so far) help toward implementation of the oracle U_f: |x>|y>→|x>|y+f(x)> on quantum computers
