PROGRAMMING:Output perfect number

Input integers a and B (6 < = a < B < 10000), output all complete numbers between [a, b], and separate the two numbers with a space. If not, output not found.
###Input example:
```in
6 100
```
###Output example:
```out
6 28
```
###Input example:
```in
100 9000
```
###Output example:
```out
496 8128
```
###Input example:
```in
1000 2000
```
###Output example:
```out
Not Found.
```







answer：If there is no answer, please comment