Snail

The purpose of this exercise is to train you in usage of simple integer operations.

Estimated workload of this exercise is 30 min.

Description

Consider a snail travels up a tree a feet each day. Then snail slides down b feet each night. Height of the tree is h feet.

Please, proceed to Snail class and write a program that prints number of days for the snail to reach the top of the tree.

Program reads a, b, h line by line. Input values are guaranteed to be positive integers.

If the snail cannot reach the top of the tree, print the message Impossible.

Examples


Input:

4
2
14

Output:

6

Input:

4
3
10

Output:

7

Input:

4
4
10

Output:

Impossible

Input:

4
4
1

Output:

1