```
class Solution(object):
def findLonelyPixel(self, picture):
dict1 = {}
dict2 = {}
matrix = []
for i in range(len(picture)):
for j in range(len(picture[0])):
if picture[i][j] == "B":
if i in dict1:
dict1[i] += 1
else:
dict1[i] = 1
if j in dict2:
dict2[j] += 1
else:
dict2[j] = 1
matrix.append([i,j])
sum = 0
for k in range(len(matrix)):
if dict1[matrix[k][0]] == 1 and dict2[matrix[k][1]] == 1:
sum += 1
return sum
```