PROGRAMMING:Output constant data training
```
The first line outputs the decimal, octal and hexadecimal forms of 2049.
The second line outputs the area of the circle with radius 2.
Third line output: I learn, I am happy.
Use the format specifier appropriately.
```
###Input example:
```in
```
###Output example:
```out
2049 04001 0x801
twelve point five six six three seven one
I study, I am happy
```
answer：If there is no answer, please comment
The first line outputs the decimal, octal and hexadecimal forms of 2049.
The second line outputs the area of the circle with radius 2.
Third line output: I learn, I am happy.
Use the format specifier appropriately.
```
###Input example:
```in
```
###Output example:
```out
2049 04001 0x801
twelve point five six six three seven one
I study, I am happy
```
answer：If there is no answer, please comment