Calculate CO2 Emissions

You are given the details of a journey divided into n segments. For each segment, you are provided with the distance d (in miles) and the fuel consumption rate f (in gallons per mile). The task is to calculate the total CO2 emissions generated over the journey using a fixed conversion factor.

The formula to compute the emissions for each segment is given by:

$$E_i = d_i \times f_i \times 20$$

and the total emissions is:

$$\text{Total Emissions} = \sum_{i=1}^{n} d_i \times f_i \times 20 $$

Output the result rounded to two decimal places.

inputFormat

The input is read from stdin and consists of:

1. An integer n on the first line, representing the number of journey segments.
2. n subsequent lines, each containing two numbers: a float d (distance in miles) and a float f (fuel consumption rate in gallons per mile), separated by space.

outputFormat

Print to stdout a single line with the total CO2 emissions in pounds, rounded to two decimal places.

## sample

1
100 0.05

100.00