''' Purpose: Demonstrate notion of mappings -- using the if-elif-else structure
             Not recommended for large number of mappings
'''


reply = input( 'Enter a Roman numeral: ' )

letter = reply.strip().upper()

if   ( letter == "I" ) :
    value = 1
elif ( letter == "V" ) :
    value = 5
elif ( letter == "X" ) :
    value = 10
elif ( letter == "L" ) :
    value = 50
elif ( letter == "C" ) :
    value = 100
elif ( letter == "D" ) :
    value = 500
elif ( letter == "M" ) :
    value = 1000
else :
    value = None

print( letter, '=', value )