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Problems

Hotel rooms

Hotel rooms

A hotel has n floors. The lobby, restaurant and gym are located on the first floor. The guestrooms are on 2-nd to n-th floors. There are m standard rooms on each floor. If each standard room can fit 3 guests, what is the maximum number of guests that all the standard rooms can accommodate?

Input

Two positive integers n and m (n, m106).

Output

Print the maximum number of guests that all the hotel standard rooms can accommodate.

Time limit 1 second
Memory limit 128 MiB
Input example #1
5 10
Output example #1
120
Author Mykhailo Medvediev
Source Programming language C