class Solution:
    def twoSum(self, numbers: List[int], target: int) -> List[int]:
        ft, bk = 0, len(numbers) - 1
        while ft < bk:
            curr_sum = numbers[ft] + numbers[bk]
            if curr_sum > target:
                bk -= 1
            elif curr_sum < target:
                ft += 1
            elif curr_sum == target:
                return [ft+1, bk+1]