Language: C++

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

#ifndef ONLINE_JUDGE
#define debarr(a,x,y)cerr<<#a<<":";for(int i=x;i<=y;i++)cerr<<a[i]<<" ";cerr<<endl;
#define debmat(mat,row,col)cerr<<#mat<<":\n";for(int i=0;i<row;i++){for(int j=0;j<col;j++)cerr<<mat[i][j]<<" ";cerr<<endl;}
#define deb(...)dbs(#__VA_ARGS__,__VA_ARGS__)
template<class S, class T>ostream &operator<<(ostream &os, const pair<S, T> &p) {return os << "(" << p.first << "," << p.second << ")";}
template<class T>ostream &operator<<(ostream &os, const vector<T> &p) {os << "["; for (auto&it : p)os << it << " "; return os << "]";}
template<class T>ostream &operator<<(ostream &os, const set<T>&p) {os << "["; for (auto&it : p)os << it << " "; return os << "]";}
template<class T>ostream &operator<<(ostream &os, const multiset<T>&p) {os << "["; for (auto&it : p)os << it << " "; return os << "]";}
template<class S, class T>ostream &operator<<(ostream &os, const map<S, T>&p) {os << "["; for (auto&it : p)os << it << " "; return os << "]";}
template<class T>void dbs(string str, T t) {cerr << str << ":" << t << "\n";}
template<class T, class...S>void dbs(string str, T t, S... s) {int idx = str.find(','); cerr << str.substr(0, idx) << ":" << t << ","; dbs(str.substr(idx + 1), s...);}
#else
#define deb(...){}
#define debarr(a,x,y){}
#define debmat(mat,row,col){}
#endif
template<class T> bool umin(T &a, T b) { return a > b ? (a = b, true) : false; }
template<class T> bool umax(T &a, T b) { return a < b ? (a = b, true) : false; }
#define pr(x) {cout << x << "\n"; return;}

#define int              long long
#define ll               long long
#define ld               long double
#define fi               first
#define se               second
#define mp               make_pair
#define pb               push_back
#define sz(x)            (int)x.size()
#define all(x)           x.begin(),x.end()
#define ini(x,y)         memset(x,y,sizeof(x))
#define rep(i,n)         for(int i=0;i<n;i++)
#define re(i,n)          for(int i=1;i<=n;i++)
#define fr(i,a,b)        for(int i=a;i<=b;i++)
#define fb(i,a,b)        for(int i=a;i>=b;i--)
typedef pair<int, int>   pii;
typedef vector<int>      vi;
typedef vector<pii>      vii;
typedef map<int, int>    mii;
typedef set<int>         si;
const int N = 1e3 + 10;

void solve()
{
	int h, w; cin >> h >> w;
	int k; cin >> k;
	map<int,map<int,int>> m;
	vi row(h+1,0),col(w+1,0);
	vi v1,v2;
	rep(i,k)
	{
	    int x,y; cin>>x>>y;
	    m[x][y]++;
	    row[x]++;
	    col[y]++;
	}
	pii a,b;
	int mx1=*max_element(all(row));
	int mx2=*max_element(all(col));
	if(mx1==w||mx2==h)
	{
	    cout<<(mx1+mx2-1)<<endl;
	    retun;
	}
	for(int i=1;i<=w;i++)
	{
	    if(col[i]==mx2) v1.pb(i);
	}
	for(int i=1;i<=h;i++)
	{
	    if(row[i]==mx1) v2.pb(i);
	}
	int f=0;
	for(auto u:v2)
    {
        for(auto v:v1)
        {
        if(m[u][v]==0) 
        {
            deb(u,v);
            f=1;
        }
        }
    }
    deb(v1,v2);
	cout << mx1+mx2-1+f << endl;


    deb(mx1,mx2);
}
signed main() {
	ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);

	int t = 1;
	//cin >> t;
	for (int i = 1; i <= t; i++) solve();
	return 0;
}

Compiler output:
a.cc: In function 'void solve()':
a.cc:65:13: error: 'retun' was not declared in this scope
   65 |             retun;
      |             ^~~~~