#0004A4

puz-COCI

There is a snail on the ground. It wants to climb to the top of a wooden pole with the height of V meters, measuring from the ground level. In one day it can climb A meters upwards, however during each night it sleeps, sliding B meters back down.


Determine the number of days it needs to climb to the top.


InputINPUT
The first and only line of input contains three integers separated by a single space: A, B and V (1 ≤ B < AV ≤ 1 000 000 000), with meanings described above.

OutputOUTPUT
The first and only line of output must contain the number of days that the snail needs to reach the top.


input :

2 1 5

output :

4



input :

5 1 6

output :

2




input :

100 99 1000000000

output :

999999901


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