PROGRAMMING:Date difference

Give two dates, find out the difference between the two days
###Input format:
There are two lines of input, each with a date
XXXX YY RR (ensure that the date given by the data is correct, and the year is within 1-4000) (multiple sets of data)
###Output format:
Output the difference between two dates by several days
###Input example:
Here is a set of inputs. For example:
```in
2017 01 01
2017 01 01
2018 01 01
2018 01 02
```
###Output example:
The corresponding output is given here. For example:
```out
0
one
```







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