Time Limit: 2 seconds
Memory Limit: 256 megabytes
In this problem we assume the Earth to be a completely round ball and its surface a perfect sphere. The length of the equator and any meridian is considered to be exactly 40 000 kilometers. Thus, travelling from North Pole to South Pole or vice versa takes exactly 20 000 kilometers.
Limak, a polar bear, lives on the North Pole. Close to the New Year, he helps somebody with delivering packages all around the world. Instead of coordinates of places to visit, Limak got a description how he should move, assuming that he starts from the North Pole. The description consists of n parts. In the i-th part of his journey, Limak should move ti kilometers in the direction represented by a string diri that is one of: "North", "South", "West", "East".
Limak isn’t sure whether the description is valid. You must help him to check the following conditions:
Check if the above conditions are satisfied and print "YES" or "NO" on a single line.
The first line of the input contains a single integer n (1 ≤ n ≤ 50).
The i-th of next n lines contains an integer ti and a string diri (1 ≤ ti ≤ 106, ) — the length and the direction of the i-th part of the journey, according to the description Limak got.
Print "YES" if the description satisfies the three conditions, otherwise print "NO", both without the quotes.
Drawings below show how Limak's journey would look like in first two samples. In the second sample the answer is "NO" because he doesn't end on the North Pole.