# Gardener

Very easy

Execution time limit is 1 second

Runtime memory usage limit is 128 megabytes

A gardener planted $N$ trees in a single day and was supposed to water each sapling with a full bucket of water. However, since it rained on the planting day, the gardener postponed the watering until some unknown $K$-th day. How many days did the gardener skip watering if, on the last day, he used $N1 $ of a bucket per tree, on the second-to-last day $N−11 $, and so forth, ensuring that, in total, he used no more than half a bucket of water per tree?

## Input

The number of trees $N$ ($0<N≤1,000,000$).

## Output

The number of days the gardener skipped watering.

## Examples

Input #3

Answer #3

Submissions 19K

Acceptance rate 29%