class Solution {
public:
    int countPrimeSetBits(int left, int right) {
        int res = 0;
        for (int i = left; i <= right; ++i){
            int temp = i;
            unsigned int flag = 1;
            int n = 0;
            while (flag){
                if (flag & temp) n++;
                flag = flag << 1;
            }
            if (n == 2 || n == 3 || n == 5 || n == 7 || n == 11 || n == 13 || n == 17 || n == 19 || n == 23 || n == 29 || n == 31 ) res++;
        }
        return res;    
    }
};