PROGRAMMING:Goldbach conjecture
Program input a positive even number greater than 6 to verify Goldbach's conjecture, and output all the formulas that express it as the sum of two odd prime numbers.
[popular science] Goldbach conjecture is one of the longest unsolved problems in number theory. This conjecture first appeared in the correspondence between Christian Goldbach of Prussia and Leonhard Euler of Switzerland in 1742. In modern mathematical language, Goldbach's conjecture can be expressed as: "any sufficiently large even number (> = 6) can be expressed as the sum of two odd primes".
###Input example:
```in
twenty
```
###Output example:
```out
20=3+17
20=7+13
20=9+11
```
answer：If there is no answer, please comment
[popular science] Goldbach conjecture is one of the longest unsolved problems in number theory. This conjecture first appeared in the correspondence between Christian Goldbach of Prussia and Leonhard Euler of Switzerland in 1742. In modern mathematical language, Goldbach's conjecture can be expressed as: "any sufficiently large even number (> = 6) can be expressed as the sum of two odd primes".
###Input example:
```in
twenty
```
###Output example:
```out
20=3+17
20=7+13
20=9+11
```
answer：If there is no answer, please comment