Simple Method || Bit Manipulation
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 minChanges(int n, int k) {
        int count = 0;
        while(n > 0 || k > 0){
            int Bitn = n & 1;
            int Bitk = k & 1;
            if(Bitn == 1 && Bitk== 0){
                count++;
            }
            if(Bitn == 0 && Bitk == 1){
                return -1;
            }
            n >>= 1;
            k >>= 1;
        }
        return count;
    }
}
```
['Java']