"""
Ex 4.3 from "A primer on..." 
Read the temperature in Fahrenheit from a file containing
a single number, convert to Celsius and print to screen.
"""

#open the file 'fahrenheit.txt' for reading:
with open('fahrenheit.txt', 'r') as infile:
    
    #skip the first three lines:
    infile.readline()   
    infile.readline()
    infile.readline()

    #read the next line, split into words and convert:
    line = infile.readline()
    words = line.split()
    F = words[-1]
    F = float(F)

C = (5 / 9) * (F - 32)
print(f'Leste {F} grader Fahrenheit fra fil, som tilsvarer {C:.1f} grader Celsius')