var guessNumber = function (n) {
    let low = 1;
    let high = n;

    while (true) {
        let mid = low + Math.floor((high - low) / 2);
        let myGuess = guess(mid);
        if (myGuess == 1) low = mid + 1;
        else if (myGuess == -1) high = mid - 1;
        else return mid;
    }
};