#include <cstdio>
using namespace std;

#define FOR(i, a, b)  for (int i = (a); i <= (b); ++ i)
#define Max(a, b)    ((a) > (b) ? (a) : (b))
#define MAXN  105
#define MAXM  20

const char iname[] = "cuplaj.in";
const char oname[] = "cuplaj.out";

int G[MAXN][MAXN], n, m;

int bst[2][1 << MAXM];

void read_in(void)
{
    int cnt_edges;
    scanf("%d %d %d", &n, &m, &cnt_edges);
    for (; cnt_edges --; )
    {
        int x, y;
        scanf("%d %d", &x, &y);
        G[x][y] = 1;
    }
}

int main(void)
{
    freopen(iname, "r", stdin);
    read_in();

    FOR (i, 1, n) FOR (cntr, 1, (1 << m) - 1)
    {
        bst[i & 1][cntr] = bst[1 ^ (i & 1)][cntr];
        FOR (j, 0, m - 1) if ((cntr >> j) & 1)
            bst[i & 1][cntr] = Max(bst[i & 1][cntr], bst[1 ^ (i & 1)][cntr ^ (1 << j)] + G[i][j + 1]);
    }
    freopen(oname, "w", stdout);
    printf("%d\n", bst[n & 1][(1 << m) - 1]);
    return 0;
}