403. Scientific Problem
Time limit per test: 0.25
second(s)
Memory limit: 65536
kilobytes
input: standard
output: standard
Once upon a time Professor Idioticideasinventor was travelling by train. Watching cheerless landscape outside the window, he decided to invent the theme of his new scientific work. All of a sudden a brilliant idea struck him: to develop an effective algorithm finding an integer number, which is
x times less than the sum of all its integer positive predecessors, where number
x is given. As far as he has no computer in the train, you have to solve this difficult problem.
Input
The first line of the input file contains an integer number
x (1 ≤
x ≤ 10
^{9}).
Output
Output an integer number — the answer to the problem.
Example(s)
sample input

sample output

1

3

sample input

sample output

2

5
