this is a shape of sample#1: ('B'=Black, '.'=white)
B...B
.B...
..B..

you must count all the streak which not belong to the streak with size more than current streak, therefor the cell's (1,2) & (2,1) & (3,2) must'nt count because they are belong to streak (1,2)->(1,4) & (2,1)->(2,2) & (3,1)->(3,2).

here some test for problem:
//////////////////////////
input:
5 5 2
1 2
3 3

output:
12
//////////////////////////
input:
5 5 4
1 2
5 3
3 1
4 4

output:
12
//////////////////////////
input:
1 1 0

output:
1
//////////////////////////
input:
1 1 1
1 1

output:
0
/////////////////////////
input:
5 5 12
1 2
1 4
2 1
2 3
2 5
3 2
3 4
4 1
4 3
4 5
5 2
5 4

output:
13
//////////////////////////////
I hope can help you.
GOOD LUCK!