On the Codeforces platform, each user has a rating to measure his level. In addition, each user will also have a title based on his rating. Recently, because user Tourist's rating exceeded 4000 points, Codeforces administrators decided to provide a new title, "Tourist", to commemorate this feat.
You also want to get this title, because it's cool to be called a "Tourist"! But your current rating is only $$$1500$$$ points, which is not enough to get this honor. So, you let the GPT predict your rating changes in the next $$$n$$$ contests. Specifically, suppose your rating is $$$b$$$ points before the $$$i$$$-th contest, then after the $$$i$$$-th contest, the GPT predicts that your rating will become $$$b+c_i$$$ points. You want to know after which of those $$$n$$$ contests you will get the title of "Tourist" for the first time, or there is no such contest.
Note that the rating may become negative during this process, and the "Tourist" title will be awarded to users with a rating of at least 4000 points.
The first line contains a single integer $$$n\ (1\le n\le 10^5)$$$, representing the number of contests in the future.
The second line contains $$$n$$$ integers $$$c_1,c_2,\dots,c_n\ (|c_i|\le 10^9)$$$. Where $$$c_i$$$ indicates the change in rating after the $$$i$$$-th contest.
Output a single integer representing the index of the contest after which you will get the title of "Tourist" for the first time. If such a contest does not exist, output '-1'.
51000 1000 1000 -5000 1000
3
520 -100 10 -150 5
-1
