dec2roman

def dec2roman(num):
    if num>3999:
        return 'out of range'
    rnum = {
      '1': ['I','X','C','M'],
      '2': ['II','XX','CC','MM'],
      '3': ['III','XXX','CCC','MMM'],
      '4': ['VI','LX','DC'],
      '5': ['V','L','D'],
      '6': ['IV','XL','CD'],
      '7': ['IIV','XXL','CCD'],
      '8': ['IIIV','XXXL','CCCD'],
      '9': ['XI','CX','MD'],
      '0': ['','','']
    }
    numstr = str(num)[::-1]
    rstr = ''
    for i in range(len(numstr)):
        rstr += rnum[numstr[i:i+1]][i]
    return rstr[::-1]

print(dec2roman(2345))
print(dec2roman(456))