Problem Description

The Snail and the Tree Stump: A snail aims to climb a tree stump that is $v$ meters high. Each day, it climbs up $a$ meters during the day and slips down $b$ meters at night. How many days will it take for the snail to reach the top of the tree stump?

Input Format

A single line containing three integers $a$, $b$, and $v$, separated by spaces.

Output Format

A single line containing one integer, representing the answer.

Sample Input and Output

Sample Input #1

2 1 5

Sample Output #1

4

Sample Input #2

5 1 6

Sample Output #2

2

Sample Input #3

100 99 1000000000

Sample Output #3

999999901

Notes

Data Size and Constraints

For $100\%$ of the data, it is guaranteed that $1 \leq b < a \leq v \leq 1 \times 10^9$.

Hints

Please derive the result formula; a simple simulation may lead to TLE.

见题面 Input 部分

见题面 Output 部分