Average Click-Through Rate Calculation

Given several advertisement campaigns, each campaign is described by two integers: the number of impressions and the number of clicks. The Click-Through Rate (CTR) for a campaign is defined as:

$$CTR = \frac{\text{clicks}}{\text{impressions}} \times 100$$

If the number of impressions is zero, the CTR should be considered 0. Your task is to calculate the average CTR of all campaigns and round the result to two decimal places. Read the input from stdin and print the output to stdout.

inputFormat

The input begins with a single integer T, representing the number of campaigns. The following T lines each contain two space-separated integers: the number of impressions and the number of clicks for a campaign.

outputFormat

Output a single line containing the average CTR rounded to two decimal places.

1
100 25

25.00