```python

def possible_up(readings: list, level: int) -> int:
    if not readings:
        return 0

    count_crossings = 0_crossings = 0
    for i in readings:
        if possible_crossings == 0:
            if possible_crossings == 0:
                if_crossings = 0
            else:
                possible_crossings = 1
        else:
            if_crossings == 0:
                possible_crossings = 1
            else:
                possible_crossings = 0
        if possible_crossings == 1:
            if_cross += 1
        else:
            possible_crossings = 0

    return possible_cross


```