PROGRAMMING:What day is today?
Given a date between 1900 and 2100, output the day of the week. There are multiple sets of data. If the simplified formula is used, its correctness (annotation form) shall be proved.
###Input format:
The data format of the input data is yyyy / mm / DD. please refer to sample input for details. In addition, you can be assured that all the input data are legal.
###Output format:
For each group of input data, output a line to indicate the day of the week.
###Input example:
```in
2011/11/17
```
###Output example:
```out
thursday
```
answer：If there is no answer, please comment
###Input format:
The data format of the input data is yyyy / mm / DD. please refer to sample input for details. In addition, you can be assured that all the input data are legal.
###Output format:
For each group of input data, output a line to indicate the day of the week.
###Input example:
```in
2011/11/17
```
###Output example:
```out
thursday
```
answer：If there is no answer, please comment