General Chemistry Lab

To graduate, Donghyeok must take a general chemistry lab course. In the final experiment he prepares a mixture, measures its temperature once every minute, and must tabulate how much the temperature changed during each one-minute interval.

Being a talented programmer, Donghyeok wrote a program that measures the mixture's temperature automatically, but he forgot to write one that computes the change in temperature.

Given the temperatures Donghyeok measured, in order, write a program that computes how much the temperature changed compared to the immediately preceding measurement.

The temperatures of the mixture are given in the order they were measured. Each temperature is between -10 and 200 degrees inclusive and may be given with up to two decimal places. After the last measurement, the value 999 is given to mark the end of the input. The temperature is measured at least twice.

For each temperature, print its difference from the immediately preceding temperature, in input order. The first temperature has no preceding temperature, so it is not printed. Each difference is always printed to exactly two decimal places.