':type picture: List[List[str]]
:rtype: int'

def findLonelyPixel(self, picture):

    (rows, cols) = (([0] * len(picture)), ([0] * len(picture[0])))
    for i in xrange(len(picture)):
        for j in xrange(len(picture[0])):
            if (picture[i][j] == 'B'):
                rows[i] += 1
                cols[j] += 1
    result = 0
    for i in xrange(len(picture)):
        if (rows[i] == 1):
            for j in xrange(len(picture[0])):
                result += ((picture[i][j] == 'B') and (cols[j] == 1))
    return result
