#include <cstdio>
#include <algorithm>
int f[1005][1005];
int edge[1005][1005];

int main(){
	int n,m,q;
	scanf("%d%d%d",&n,&m,&q);
	for(int i = 0; i < q; i++){
		int u,v;
		scanf("%d%d",&u,&v);
		edge[u][v] = 1;
	}
	f[0][0] = 0;
	for(int i = 1; i <= n; i++){
		for(int j = 0; j <= m; j++){
			f[i][j] = 0;
			if(j){
				f[i][j] = std::max(f[i][j], f[i][j-1]);
				if(edge[i][j]){
					f[i][j] = std::max(f[i][j], f[i-1][j-1]+1);
				}
			}
		}
	}
	printf("%d\n",f[n][m]);
	return 0;
}