from collections import deque
from typing import Iterator, Deque, Callable, Tuple
from sys import stdin

import itertools


class Scanner:
    _tokens: Deque[str]

    def __init__(self):
        self._tokens = deque()

    def read(self) -> str:
        if len(self._tokens) == 0:
            self._tokens.extend(stdin.readline().split())
        return self._tokens.popleft()

    def read_int(self) -> int:
        return int(self.read())

    def read_ints(self, n: int) -> Iterator[int]:
        return [self.read_int() for _ in range(n)]

    @staticmethod
    def readline(func: Callable = str):
        return map(func, stdin.readline().split())


cin = Scanner()


def main():
    n = cin.read_int()
    a = [*map(lambda x: bool(x), cin.read_ints(n))]
    ans_all = n * (n + 1) // 2

    a_start = -1
    for i in range(n):
        if a[i]:
            if a_start == -1:
                a_start = i
        else:
            if a_start != -1:
                tmp = i - a_start
                ans_all -= tmp * (tmp + 1) // 2
                a_start = -1

    if a_start != -1:
        tmp = n - a_start
        ans_all -= tmp * (tmp + 1) // 2

    print(ans_all)

if __name__ == '__main__':
    main()