CF418E Tricky Password

In order to ensure confidentiality, the access to the "Russian Code Cup" problems is password protected during the problem development process. To select a password, the jury can generate a special table that contains $ n $ columns and the infinite number of rows. To construct a table, the first row is fixed, and all the others are obtained by the following rule: In the row $ i $ at position $ p $ there is a number equal to the number of times $ a[i-1][p] $ occurs on the prefix $ a[i-1][1...\ p] $ . To ensure the required level of confidentiality, the jury must be able to perform the following operations: - Replace number $ a[1][p] $ by $ v $ and rebuild the table. - Find the number $ a[x][y] $ , which will be the new password. Doing all these steps manually is very tedious, so the jury asks you to help him. Write a program that responds to the request of the jury.

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