PROGRAMMING:6174 black hole
Program input a 4-bit positive integer, verify 6174 black hole problem, output its operation process as required.
6174 is a famous constant, which was proposed by the Indian mathematician kabulek. Kabulek found that: any four digit positive integer that is not the same as four digits, as long as the numbers are rearranged, combined into the largest number and the smallest number, and then subtracted, repeat the above steps, 6174 will appear within seven times.
For example: 80458540-0458 = 80828820-0288 = 85328532-2358 = 6174.
###Input example:
```in
five thousand six hundred and seventy-eight
```
###Output example:
```out
8765-5678=3087
8730-0378=8352
8532-2358=6174
```
answer：If there is no answer, please comment
6174 is a famous constant, which was proposed by the Indian mathematician kabulek. Kabulek found that: any four digit positive integer that is not the same as four digits, as long as the numbers are rearranged, combined into the largest number and the smallest number, and then subtracted, repeat the above steps, 6174 will appear within seven times.
For example: 80458540-0458 = 80828820-0288 = 85328532-2358 = 6174.
###Input example:
```in
five thousand six hundred and seventy-eight
```
###Output example:
```out
8765-5678=3087
8730-0378=8352
8532-2358=6174
```
answer：If there is no answer, please comment