# your code goes here
class Solution(object):
    def singleNonDuplicate(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        l = 0
        h = len(nums)-1

        while(l<h):
            mid = (l+h)//2
            if mid % 2 == 1:
                mid = mid-1

            if nums[mid] == nums[mid+1]:
                l = mid + 2
            else:
                h = mid
        
        return nums[l]