###### Category

###### Similar Problems

## 0743. Scientific Problem

###### Time limit : 1000 ms

Memory limit : 64 mb

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.

№ |
Input |
Output |

1 |
1 |
3 |

2 |
2 |
5 |

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