simple C
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
```c []
int smallestNumber(int n) {
    int k = 0; 
    while(n)
    {
        k++;
        n >>= 1;
    }
    return pow(2,k) - 1;
}
```
['C']