Easy Solution
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```csharp []\npublic class Solution {\n    public int MinChanges(int n, int k) {\n         int bitn,bitk;\n        int count=0;\n        while(n!=0 || k!=0){\n            bitn=n&1;\n            bitk=k&1;    \n            //Console.WriteLine(bitn+"*"+bitk);        \n            if(bitk==1 && bitn==0)return -1;\n            if(bitk==0 && bitn==1)count++;\n            n=n>>1;            \n            k=k>>1;\n            //Console.WriteLine(n+"*"+k);\n        }\n        return count;\n    }\n}\n```
['C#']