```
def findLonelyPixel(self, picture):
result = 0
row = [0 for i in range(len(picture))]
col = [0 for i in range(len(picture[0]))]
for m in range(len(picture)):
for n in range(len(picture[0])):
if picture[m][n] == 'B':
row[m]+= 1
col[n]+= 1
for m in range(len(picture)):
for n in range(len(picture[0])):
if picture[m][n] == 'B' and row[m] == 1 and col[n] == 1:result+=1
return result
```