n,m,q = map(int, input().split())
M = [[0]*m for i in range(n)]
for i in range(q):
    a,b = map(int, input().split())
    a,b =a-1, b-1
    M[a][b] = 1

dp = [[0]*(m+1) for i in range(n+1)]
for i in range(n):
    for j in range(m):
        if M[i][j] == 1:
            dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j]+1)
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i+1][j])
        dp[i+1][j+1] = max(dp[i+1][j+1], dp[i][j+1])
print(dp[n][m])