My solution is to deal with the 9 and 4 ，because this two number is the line that make the notation change

```
class Solution(object):
def intToRoman(self, num):
"""
:type num: int
:rtype: str
"""
decimalisms = ('I','X','C','M')
quinarys = ('V','L','D')
pos = 0
roman = ""
while num > 0:
mod = num%10
num = num/10
if mod == 9:
roman =decimalisms[pos] + decimalisms[pos+1] + roman
elif mod >= 4:
roman = decimalisms[pos]*(5-mod) + quinarys[pos] + decimalisms[pos]*(mod-5) + roman
elif mod > 0:
roman = decimalisms[pos]*mod+roman
pos += 1
return roman
```