from typing import List


def nums_substr(target_num: int, all_nums: List[int]) -> int:
    substr_nums = 0
    lp, rp = 0, 0
    current_sum = all_nums[0]
    for lp in range(len(target_num)):

        while rp < len(all_nums) and current_sum <= target_num:
            rp += 1
            if rp < len(all_nums) and current_sum < target_num:
                current_sum += all_nums[rp]
            elif rp == len(all_nums) and current_sum < target_num:
                substr_nums += 1

        if current_sum == target_num:
            substr_nums += 1
            current_sum -= all_nums[lp]
            lp += 1

        elif current_sum > target_num:
            current_sum -= all_nums[lp]
            lp += 1
        else:
            break

    return substr_nums


if __name__ == '__main__':
    # target_num = int(input())
    # nums = [int(x) for x in input().split()]

    target_num = 1
    nums = [int(x) for x in '1010']
    print(nums_substr(target_num, nums))