Write a function named `coin_flip`

that accepts as its parameter a string `$filename`

, opens the file with that filename, and reads its contents as a sequence of whitespace-separated tokens.

Assume that the input file data represents results of sets of coin flips.
A coin flip is either the letter H or T, or the word Heads or Tails, in either upper or lower case, separated by at least one space.
You should read the sequence of coin flips and print the number of heads and the percentage of heads in that line, rounded to the nearest whole number.
If this percentage is 50% or greater, you should print a "You win!" message; otherwise, print "You lose!".
For example, consider the following input file:

H T H H T
Tails taIlS tAILs TailS heads HEAds
hEadS

For the input above, your function should produce the following output:

6 heads (50%)
You win!

The format of your output must exactly match that shown above.
You may assume that the file contains at least 1 token of input, and that no tokens other than heads/tails or H/T will be in the lines.
You may assume that the input file exists and is readable.

*Constraints:*
Your solution should read the file only once, not make multiple passes over the file data.