Losing a passport is not a pleasant experience. An identity document is needed constantly, to obtain any kind of certificate, to carry out banking operations, to conclude transactions, etc. Every citizen from the age of 14 is required to have a passport, and long-term residence without it is punishable by a large fine.
After making sure that the passport is gone, immediately report the loss (or theft) and make a new one. Don't wait for someone to find and bring it to you. Delays here are fraught with a large fine, as well as illegal actions on the part of fraudsters. You cannot be sure that no one is using your document for their own purposes, to take a loan in your name, etc. Having written a statement, you can rest assured that even if something like this happens, the police will know that during this period of time you did not have a passport and you could not do it. And in the federal database there will be information that the missing passport is no longer valid. Therefore, immediately go to the nearest police station, tell the district police officer and write a statement about the loss of the passport under unknown circumstances (or about theft if the document was stolen). The application will be registered and you will be given a tear-off coupon stating that it has been accepted from you. A check will be carried out on the fact of loss, which can take from two weeks to a month. At the end of the check, you will receive a letter about its results. With this paper, go to the passport office at your place of residence, pay the state fee and apply for the restoration of your passport. To do this, you will need a number of documents (birth certificate, certificate of place of residence, military ID for men), four black and white or color photographs 35x45 mm, a receipt for payment of the duty. You will be issued a new passport within two months, but without waiting for the conclusion on the results of the check, you can go to the passport office and get a temporary identity card. Do not forget to take with you the coupon that was given to you by the police after receiving your statement of loss. Until a new passport is issued, this certificate will replace it for you.