Find all Exchange mailboxes with given user rights

# Find all Exchange mailboxes on which user "$adUser" has "$accRights" access rights
# First expression just to narrow search from 'А*' to 'Я*' (from first to last letter;
#      Russian mailbox identities have names like "Алла Пугачёва" or "Яков Свердлов")

$adUser = 'domain\User'
$accRights = 'FullAccess'

[int][char]'а'..[int][char]'я' | foreach { get-mailbox "$([char]$_)*" -erroraction SilentlyContinue | Get-MailboxPermission  |  where { ($_.AccessRights -contains $accRights ) -and ($_.User -like $adUser) } } | ft Identity, User, AccessRights