PROGRAMMING:Finding the spherical distance between any two points on the equator
It is known that the equatorial radius of the earth is 6378.137 km, and the longitude (in degrees) of any two points on the equator is known. A program is written to calculate the spherical distance between the two points. All real numbers are required to use double type, and the approximate value of PI is 3.141592653589793.
It is suggested that east longitude and west longitude can be distinguished by positive and negative, that is, east longitude is positive and west longitude is negative.
###Input format:
Enter two real numbers representing longitude in the interval [- 180180] in a row, separated by spaces.
###Output format:
Output the value of spherical distance, keep 3 decimal places, and finally wrap.
###Input example:
```in
-96.3 100.6
```
###Output example:
```out
eighteen thousand one hundred and fifty-six point two zero nine
```
answer：If there is no answer, please comment
It is suggested that east longitude and west longitude can be distinguished by positive and negative, that is, east longitude is positive and west longitude is negative.
###Input format:
Enter two real numbers representing longitude in the interval [- 180180] in a row, separated by spaces.
###Output format:
Output the value of spherical distance, keep 3 decimal places, and finally wrap.
###Input example:
```in
-96.3 100.6
```
###Output example:
```out
eighteen thousand one hundred and fifty-six point two zero nine
```
answer：If there is no answer, please comment