Dinic

#include<bits/stdc++.h>
using namespace std;
const int N=1e5+5,M=1e5+6,inf=2147483647;
#define int long long
struct Edge{
	int to,nxt,value;
}edges[M];
int n,m,e;
int s,t,u,v;
int cnt=1;
int head[N],cur[N];
int dep[N];
void addedge(int u,int v,int w){
	edges[++cnt]={v,head[u],w};
	head[u]=cnt;
}
int max_flow;
bool bfs(){
	for(int i=0;i<=n+m+1;i++){
		dep[i]=inf;
	} 
	memcpy(cur,head,sizeof head);
	queue<int>Q;
	dep[s]=1;
	Q.push(s);
	while(!Q.empty()){
		int u=Q.front(); Q.pop();
		for(int i=head[u];i;i=edges[i].nxt){
			int v=edges[i].to;
			if(dep[v]>dep[u]+1&&edges[i].value){
				dep[v]=dep[u]+1;
				Q.push(v);
			}
		} 
	}
return dep[t]!=inf;
}
int dfs(int u,int flow){
	if(u==t){
		max_flow+=flow;
		return flow;
	}
	int used=0;
	for(int i=cur[u];i;i=edges[i].nxt){
		cur[u]=i;
		int v=edges[i].to;
		if(dep[v]==dep[u]+1){
			if(edges[i].value){
				int rflow=dfs(v,min(edges[i].value,flow-used));
				if(rflow){
					used+=flow;
					edges[i].value-=rflow;
					edges[i^1].value+=rflow;
					if(used==flow){
						return used;
					}
				}
			}
		}
	}
return used;
}
int dinic(){
	while(bfs()){
		dfs(s,inf);
	}
	return max_flow;
}
signed main(){
	cin.tie(0)->sync_with_stdio(0);
	cin>>n>>m>>e;
	s=0,t=n+m+1;
	while(e--){
		cin>>u>>v;
		addedge(u,v+n,1);
		addedge(v+n,u,0);
	}
	for(int i=1;i<=n;i++){
		addedge(s,i,1);
	}
	for(int i=n+1;i<=n+m;i++){
		addedge(i,t,1);
	}
	cout<<dinic();
return 0;
}