// Forward declaration of guess API.

// @param num, your guess

// @return -1 if my number is lower, 1 if my number is higher, otherwise return 0

int guess(int num);

class Solution {

public:

    int guessNumber(int n) {

        int start = , end = n;

        while(start < end){

            int mid = start + (end - start)/;

            int res = guess(mid);

            if(res == )

                return mid;

            else if(res < )

                end = mid - ;

            else

                start = mid + ;

        }

        return start;

    }

};