B'Recently Vasya got interested in finding extra-terrestrial intelligence. He made a simple extra-terrestrial signals xe2 x80 x99 receiver and was keeping a record of the signals for n days in a row. Each of those n days Vasya wrote a 1 in his notebook if he had received a signal that day and a 0 if he hadn xe2 x80 x99t. Vasya thinks that he has found extra-terrestrial intelligence if there is a system in the way the signals has been received, i.e. if all the intervals between successive signals are equal. Otherwise, Vasya thinks that the signals were sent by some stupid aliens no one cares about. Help Vasya to deduce from the information given by the receiver if he has found extra-terrestrial intelligence or not. The first line contains integer n (3 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89100) -- amount of days during which Vasya checked if there were any signals. The second line contains n characters 1 or 0 -- the record Vasya kept each of those n days. It xe2 x80 x99s guaranteed that the given record sequence contains at least three 1s. If Vasya has found extra-terrestrial intelligence, output YES, otherwise output NO.'...