CF962A Equator

已知 Polycarp 共有 $n$ 天准备编程竞赛，他每天预计做的题数为 $a_i$，请问直到第几天能做完所有题目的一半或更多。

第一行，一个整数 $n$。 第二行，$n$ 个整数，表示 $a_i$。

一个整数，表示答案。

In the first example Polycarp will celebrate the equator on the evening of the second day, because up to this day (inclusive) he will solve $ 4 $ out of $ 7 $ scheduled problems on four days of the training. In the second example Polycarp will celebrate the equator on the evening of the third day, because up to this day (inclusive) he will solve $ 6 $ out of $ 12 $ scheduled problems on six days of the training.