simple One-liner 100% java
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```java []
class Solution {
    public int smallestNumber(int n) {
    int mask = (Integer.highestOneBit(n) << 1) - 1; 
        
       return mask; 
    }
}
```
['Java']