from functools import lru_cache


class Board:
    def __init__(self, board: list[int]) -> None:
        self.board = board

    @lru_cache
    def calc_move_times(self, mass: int, is_shine: bool) -> int:
        if mass == len(self.board) - 1:
            return 0

        if not is_shine:
            return 0

        if self.board[mass] == is_shine:
            return 1 + self.calc_move_times(mass+1, not self.board[mass+1])
        else:
            return 1 + self.calc_move_times(mass+1, self.board[mass+1])


def main():
    N = int(input())
    A = list(map(int, input().split()))
    board = Board(A)
    print(sum(map(lambda arg: board.calc_move_times(arg[0], arg[1]),
                  (zip(reversed(range(N)), reversed(A))))))


if __name__ == "__main__":
    main()