simple
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
```rust []
impl Solution {
    pub fn smallest_number(mut n: i32) -> i32 {
        let mut count = 0;
        while n > 0 {
            n /= 2;
            count += 1;
        }
        (0..count).fold(0, |acc, i| acc + 2i32.pow(i))
    }
}
```
['Rust']