#define _CRT_SECURE_NO_WARNINGS
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING

#include <bits/stdc++.h>

using namespace std;
int fa[1 << 20 | 1];

int find(int x) { return fa[x] == x ? x : fa[x] = find(fa[x]); }

void link(int x, int y) { fa[find(y)] = find(x); }

int main() {
    int m, n, k, ans = 0;
    scanf("%d%d%d", &m, &n, &k);
    for (int i = m * n; i; i--) fa[i] = i;
    for (int a, b; k--;) {
        scanf("%d%d", &a, &b);
        int fa = find(a), fb = find(b);
        link(a, b);
    }
    set<int> S;
    for (int i = m * n; i; i--) S.insert(find(i));
    printf("%d", S.size());
    return 0;
}