PROGRAMMING:Verification of Goldbach's conjecture

###Task description
```
Verify the Goldbach conjecture, that is, any even number greater than or equal to 6 can be expressed as the sum of two prime numbers.
```
###Input format:
```
Enter only one positive integer X（ x<=2000)
```
###Output format:
```
If x is not an even number greater than or equal to 6, a line is output:
Error!
Otherwise, output all the decomposition forms of this number
x=y+z
Where x is the number to be verified, y and Z satisfy y + Z = x, and Y < = Z, y and Z are prime numbers.
If there are multiple decomposition forms, all decomposition forms are output in ascending order of Y, one decomposition expression for each line.
Note that the output does not have extra spaces.
```
###Input example:
```in
seven
```
###Output example:
```out
Error!
```
###Input example:
```in
ten
```
###Output example:
```out
10=3+7
10=5+5
```
###Title Source
###Input example:
```in
one hundred
```
###Output example:
```out
100=3+97
100=11+89
100=17+83
100=29+71
100=41+59
100=47+53
```
###Title Source
Selected from openjudge website, online address: http://sdau.openjudge.cn/c/059/







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