Type of	Number of qubits	Number of	Number of
Sentinel	for N sentinels	single qubit gates	two qubit gates
Positional	N	from 0	0
sentinel		to $2N$
Hidden	$2N$	from $2N$	$2N$
sentinel		to $4N$
The resource comparison between positional and hidden sentinels
is done for N sentinels.