Problem said we couldn't convert to int, but didn't say we can't convert from int to str ;)

```
class Solution(object):
def addStrings(self, num1, num2):
"""
:type num1: str
:type num2: str
:rtype: str
"""
def convert(c):
return ord(c)-ord('0')
x1=x2=0
for i in num1:
x1=x1*10+ convert(i)
for j in num2:
x2=x2*10+convert(j)
x=x1+x2
return str(x)
```