Understanding data types and math: summation, temperature conversion 2

a = int (input( ' To convert from Celsius to Fahrenheit please press 1\nTo convert from Fahrenheit to Celsius please press 2\n ' ))
 if a == ' 1 ' :
    c = float (input( ' Please enter the temperature in Celsius: ' ))
    f = c* 9 / 5 + 32 
    print( ' Celsius {:.2f} is Fahrenheit {:.2f} ' .format(c,f))
 else :
    f = float (input( ' Please enter the temperature in Fahrenheit: ' ))
    c = 5/9*(f-32)
    print( ' Fahrenheit {:.2f} is Celsius {:.2f} ' .format(f,c))