Bessie the cow is competing in a cross-country skiing event at the winter Moolympic games. She starts out at a speed of 1 meter per second. However, as she becomes more tired over time, she begins to slow down. Each time Bessie slows down, her speed decreases: she moves at ½ meter per second after slowing down once, then ⅓ meter per second after slowing down twice, and so on.

You are told when and where Bessie slows down, in terms of a series of events. An event "T 17" means that Bessie slows down at time 17 seconds into the race. An event "D 10" means that Bessie slows down at distance 10 meters from the start.

Given a list of N such events (1 <= N <= 10,000), please compute the amount of time, in seconds, for Bessie to travel an entire kilometer. Round your answer to the nearest integer second (0.5 rounds up to 1).

(This problem appeared identically as the Bronze problem 2 and Silver problem 1 of the USACO 2014 January contest.)

Line 1: The value of N.

Lines 2..1+N: Each line is of the form "T x" or "D x", indicating a time event or a distance event. In both cases, x is an integer guaranteed to place the event before Bessie reaches one kilometer of total distance. Multiple events may occur simultaneously. Events may not be listed in order.

The total time required for Bessie to travel 1 kilometer.

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