https://www.lanqiao.cn/courses/31016/learning/?id=1898140&compatibility=false

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> PII;
typedef vector<long long> VI;
#define rep(i,a,n) for (int i=a;i<=n;i++)
#define per(i,a,n) for (int i=a;i>=n;i--)
#define pb(i) push_back(i)
#define int long long
#define INF 0x3f3f3f3f
#define oz  998244353
#define endl '\n'
#define N 2000100
const int mod = 1e9 + 7;


//int p[N],si[N];
//int find(int x) {
//  if(x != p[x]) p[x] = find(p[x]);
//  return p[x];
//}
//size[find(b)] += size[find(a)];
//p[find(a)] = find(b);


int n, m, k, p[N], res;

int find(int x) {
    if (x == p[x])return p[x];

    p[x] = find(p[x]);
    return p[x];
}

void solve() {
    cin >> n >> m >> k;


    rep(i, 1, n * m)p[i] = i;

    while (k --) {
        int a, b;
        cin >> a >> b;

        p[find(a)] = find(b);
    }


    rep(i, 1, n * m) {
        if (p[i] == i)res ++;
    }

    cout << res << endl;



}

signed main() {

    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);

    int T = 1;
//  cin >> T;
    while (T --)

        solve();

    return 0;
}