PROGRAMMING:Finding the sum of the first n terms of the n-th sequence
This problem requires programming to calculate the sum of the first n items of the sequence 1 + 1 / 2 + 1 / 3 +.
###Input format:
The input gives a positive integer n on one line.
###Output format:
In one line, output the value s of partial sum in the format of "sum = s", accurate to 6 decimal places. The calculation results should not exceed the double precision range.
###Input example:
```in
six
```
###Output example:
```out
sum = 2.450000
```
answer：If there is no answer, please comment
###Input format:
The input gives a positive integer n on one line.
###Output format:
In one line, output the value s of partial sum in the format of "sum = s", accurate to 6 decimal places. The calculation results should not exceed the double precision range.
###Input example:
```in
six
```
###Output example:
```out
sum = 2.450000
```
answer：If there is no answer, please comment