Simple js solution
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
```javascript []
/**
 * @param {number} n
 * @return {number}
 */
var smallestNumber = function (n) {

    if(n<=1) return n
    let x = 1
    while (x <= n) {
        x = x * 2
    }
    return x - 1

};
```
['JavaScript']