Coding Gurukul: Revision Challenge

Problem statement

A learner solves 1 problem on day 1, 2 on day 2, 3 on day 3, and so on. Given a target T, find the first day when the total solved is at least T. Use a loop to accumulate the daily work until the target is reached. For T = 8, the totals are 1, 3, 6, 10, so the answer is day 4.

Input format

One integer T, the target number of solved problems.

Output format

Print the minimum number of days needed.

Constraints

1 ≤ T ≤ 1000000000

Sample input

8

Sample output

4