User messaging

Below is a table schema for a new messaging app. The table contains send/receive message data for the application's users.

table name: user_messaging
     time_stamp (integer)             # timestamp, epoch seconds
     sender_id (integer)              # id of the message sender
     receiver_id (integer)            # id of the message receiver

Question: What fraction of active users communicate with at least 25 unique people on April 2nd, 2018?