PROGRAMMING:The problem of monkeys eating peaches

A monkey picked several peaches on the first day, ate half of them immediately, and then ate one more; The next morning, he ate half of the remaining peaches and another one. After that, every morning I ate the remaining half of the previous day plus one. When I wanted to eat again in the morning, I saw that there was only one peach left. Q: how many peaches were picked on the first day?
###Input format:
Input gives a positive integer $$n $$($$1 < n / Le 10 $$) in one line.
###Output format:
Output the number of peaches picked on the first day in a row.
###Input example:
```in
three
```
###Output example:
```out
ten
```






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