FARM1 C++

#include<bits/stdc++.h>
using namespace std;
#define ll long long

ll m, n, a, b, f[105][105], k;

void check(ll a, ll b) {
    for (int i = a - 2; i <= a + 2; i++) {
        for (int j = b - 2; j <= b + 2; j++) 
            f[max(i, 1)][max(j, 1)] = 1;
    }
}

void giai() {
    for (int i = 1; i <= m; i++)
        for (int j = 1; j <= n; j++) f[i][j] = 0;
    for(int i=1;i<=k;i++) {
        cin >> a >> b;
        check(a, b);
    }
    ll d = 0;
    for (int i = 1; i <= m; i++)
        for (int j = 1; j <= n; j++)
            if (f[i][j] == 0) d++;
    cout << d;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    //freopen("farm.inp", "r", stdin);
    //freopen("farm.out", "w", stdout);
    cin >> m >> n >> k;
    xuli();    
    giai();
}