2 5 10
2 2
1 1
1 4
2 1
1 2
1 5
2 4
2 5
1 3
2 3
 2 2 2
1 1
2 2
 3 3 9
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
 7 5 35
5 3
3 5
1 1
2 5
6 4
7 2
5 1
3 4
6 5
7 3
4 1
2 2
4 2
2 4
4 3
3 3
6 1
1 2
4 5
1 3
2 1
5 5
7 5
7 1
6 2
1 4
1 5
3 2
4 4
5 2
2 3
6 3
7 4
5 4
3 1
 1 5 4
1 1
1 2
1 4
1 5
 1 1 1
1 1
 5 7 21
4 4
4 5
5 5
5 6
5 7
5 1
5 2
4 2
3 2
3 1
3 7
3 6
2 6
1 6
1 7
1 1
1 2
1 3
1 4
2 4
3 4
 2 1 1
1 1
 2 2 4
2 1
1 1
1 2
2 2
 3000 3000 1
2222 738
 5 7 35
1 2
2 3
5 1
5 7
4 4
5 3
3 1
2 6
4 5
2 7
4 1
2 1
2 2
1 7
5 6
3 6
4 6
1 6
1 1
3 3
3 4
4 2
2 5
5 5
3 5
2 4
1 5
1 3
4 3
5 4
1 4
3 7
4 7
3 2
5 2
 5 4 1
4 1
 3 4 12
2 3
3 2
2 2
2 1
1 2
3 1
1 4
1 3
3 3
2 4
3 4
1 1
 3 3 3
1 1
2 2
3 3

8
 1
 6
 26
 4
 0
 20
 0
 2
 1
 28
 1
 9
 3

#!/usr/bin/env python3
import queue, sys

def find(k, parent):
    while parent[k] != k:
        parent[k] = parent[parent[k]]
        k = parent[k]
    return k

def merge(a, b, parent):
    ka = parent[a]
    kb = parent[b]
    parent[ka] = kb

CON8 = [(-1, 0), (1, 0), (0, 1), (0, -1), (-1, -1), (-1, 1), (1, -1), (1, 1)]

def keys(grid, parent, y, x):
    R = len(grid)
    C = len(grid[0])
    keys = set()
    for dy, dx in CON8:
        ny = y + dy
        nx = x + dx
        if ny < 0 or ny == R:
            continue
        if nx < 0 or nx == C:
            continue
        if not grid[ny][nx]:
            continue
        key = find((ny, nx), parent)
    return keys


def check(grid, parent, y, x, C):
    if grid[y][x]:
        return True
    neigA = keys(grid, parent, y, x)
    neigB = keys(grid, parent, y, x+C)
    inter = neigA.intersection(neigB)
    return len(inter) > 0


if __name__ == '__main__':
    R, C, I = map(int, input().split())
    grid = [[False]*C*2 for _ in range(R)]
    res = 0
    parent = dict()
    for _ in range(I):
        y, x = map(int, input().split())
        y -= 1
        x -= 1
        if grid[y][x]:
            continue

        if check(grid, parent, y, x, C):
            grid[y][x] = True
            grid[y][x+C] = True
        else:
            res += 1
            #print('destroyed', y, x, file=sys.stderr)
    print(I - res)
