为什么40？

#include<iostream>
#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#define MAXN 3000+10
using namespace std;
const int INF=1<<30;
inline int read(){
	int out=0;
	char c=getchar();
	while(c<48||c>57) c=getchar();
	while(c<=57&&c>=48){
		out=(out<<1)+(out<<3)+c-48;
		c=getchar();
	}
	return out;
}
inline void write(int x){
	if(x>9) write(x/10);
	putchar(x%10+48);
}
inline int min(int a,int b){return a<b?a:b;}
struct Edge{int u,v,cap,flow;};
struct dinic{
	vector<Edge>edge;
	vector<int>node[MAXN];
	int cur[MAXN],dis[MAXN];
	int n,m=0,s,t;
	void addedge(int u,int v,int cap){
		edge.push_back(Edge{u,v,cap,0});
		edge.push_back(Edge{v,u,0,0});
		node[u].push_back(m++);
		node[u].push_back(m++);
	}
	bool bfs(){
		bool vis[MAXN];
		memset(vis,0,sizeof(vis));
		queue<int>q;
		q.push(s);
		vis[s]=1;
		dis[s]=0;
		while(!q.empty()){
			int u=q.front();
			q.pop();
			for(int i=0;i<node[u].size();++i){
				Edge& e=edge[node[u][i]];
				if(!vis[e.v]&&e.cap>e.flow){
					dis[e.v]=dis[u]+1;
					vis[e.v]=1;
					q.push(e.v);
				}
			}
		}
		return vis[t];
	}
	int dfs(int u,int a){
		if(u==t||!a) return a;
		int flow=0,f;
		for(int& i=cur[u];i<node[u].size();++i){
			Edge& e=edge[node[u][i]];
			if(dis[u]+1==dis[e.v]&&(f=dfs(e.v,min(a,e.cap-e.flow)))>0){
				flow+=f;
				e.flow+=f;
				edge[node[u][i]^1].flow-=f;
				a-=f;
				if(!a) break;
			}
		}
		return flow;
	}
	int maxflow(int s,int t){
		this->s=s,this->t=t;
		int flow=0;
		while(bfs()){
			memset(cur,0,sizeof(cur));
			flow+=dfs(s,INF);
		}
		return flow;
	}
}G;
void init(){
	int n=read();
	int p=read();
	int q=read();
	G.s=0;G.t=1000;
	for(int i=1;i<=p;++i) G.addedge(0,i,1);
	for(int i=1;i<=n;++i) G.addedge(p+i,p+n+i,1);
	for(int i=1;i<=q;++i) G.addedge(p+n*2+i,G.t,1);
	for(int i=1;i<=n;++i){
		for(int j=1;j<=p;++j){
			int a=read();
			if(a) G.addedge(j,p+i,1);
		}
	}
	for(int i=1;i<=n;++i){
		for(int j=1;j<=q;++j){
			int a=read();
			if(a) G.addedge(p+n+i,p+n*2+j,1);
		}
	}
}
int main(){
	init();
	cout<<G.maxflow(G.s,G.t);
	return 0;
}