BlueBook

The population of a certain country has been increasing at an average rate of ~P~ percent each year. Assuming that the population was ~A~ in year ~Y~, write a program that finds the year in which the population will reach ~B~ if the growth pattern continues.

Input, Output

The order of input will be ~P~, ~A~, ~Y~, ~B~. Output should be in whole numbers (i.e. no decimals).

Sample Input

5.5 24000000 1980 100000000

Sample Output

2007