PROGRAMMING:5-3 calculates the sum of 1-1 / 2 + 1 / 3-1 / 4 + 1 / 5 +... + 1 / m

5-3 calculate the sum of sum = 1-1 / 2 + 1 / 3-1 / 4 + 1 / 5 +... + 1 / m, where m is input from the keyboard, and the output result retains 4 digits after the decimal point.
###Input format:
For example, enter a positive integer.
###Output format:
For example: output decimal.
###Input example:
Here is a set of inputs. For example:
```in
one
```
###Output example:
The corresponding output is given here. For example:
```out
one
```







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