PROGRAMMING:Fibonacci sequence

Known Fibonacci sequence definition: F (0) = 0; f(1) = 1; f(n) = f(n-1) + f(n-2); Then your task is to find f (n) according to the known n (n < 30);
###Input format:
###Output format:
###Input example:
Here is a set of inputs. For example:
```in
one
two
three
four
five
```
###Output example:
The corresponding output is given here. For example:
```out
one
one
two
three
five
```







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