vladimir but when you configure Pop access in gmail, you can choose to keep your mails in inbox folder, then you don't have to delete mails from gmail.
Just go to gmail account:
Go to Settings / Forwarding and POP / and find under POP download
2. When messages are accessed with POP and choose
keep Gmail's copy in the inbox. With this option the messages from gmail they are not deleted.
Greets
Deivid
Comment/Reply (w/o sign-up)