position = [
    ['2019-05-01', '- 6'],
    ['2019-05-02', '+5'],
    ['2019-05-03', ' 5'],
    ['2019-05-04', '4'],
    ['2019-05-05', '5'],
    ['2019-05-06', '5'],
    ['2019-05-07', '4'],
    ['2019-05-08', 'Error 5'],
    ['2019-05-09', '3'],
    ['2019-05-10', '3'],
]
count_lines = 0
total_position = 0

for row in position:
    count_lines += 1
    level = int(row[1])
    total_position += level
print(total_position / count_lines)