def checksum_min_max(sheet_file):
    """Return the sum of each row's max - min"""
    result = 0
    with open(sheet_file) as f:
        sheet_list = f.readlines()

        for row in sheet_list:
            int_row = [int(i) for i in row.split('\t')]
            result = result + (max(int_row) - min(int_row))

    return result