A system includes a server including first circuitry and a plurality of terminals, each of which includes second circuitry respectively. The first circuitry is configured to store primes assigned to the plurality of terminals, acquire two or more primes assigned to two or more terminals that and are destinations of contents, calculate a first product of the two or more primes, and transmit first notification data including the first product and the contents to the plurality of terminals. The second circuitry is configured to store an assigned prime, receive the first notification data, determine whether the first product included in the first notification data is divisible by the assigned prime, and acquire, from the first notification data, the contents included in the first notification data based on a result of a determination.
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