1 #include <queue>
 2 #include <ctype.h>
 3 #include <cstdio>
 4 #include <iostream>
 5 
 6 using namespace std;
 7 
 8 const int MAXN=10100;
 9 const int INF=0x7fffffff;
10 
11 int n,m,src,decc;
12 
13 inline void read(int&x) {
14     register char c=getchar();
15     for(x=0;!isdigit(c);c=getchar());
16     for(;isdigit(c);x=x*10+c-48,c=getchar());
17 }
18 
19 struct node {
20     int to;
21     int next;
22     int val;
23 };
24 node e[MAXN];
25 
26 int head[MAXN],cur[MAXN],tot=1;
27 
28 int depth[MAXN];
29 
30 queue<int> q;
31 
32 inline void add(int x,int y,int z) {
33     e[++tot].to=y;
34     e[tot].val=z;
35     e[tot].next=head[x];
36     head[x]=tot;
37 }
38 
39 bool bfs() {
40     for(int i=0;i<=tot;++i) depth[i]=-1,cur[i]=head[i];
41     while(!q.empty()) q.pop();
42     q.push(src);
43     depth[src]=0;
44     while(!q.empty()) {
45         int u=q.front();
46         q.pop();
47         for(int i=head[u];i!=-1;i=e[i].next) {
48             int to=e[i].to;
49             if(e[i].val&&depth[to]==-1) {
50                 depth[to]=depth[u]+1;
51                 q.push(to);
52                 if(to==decc) return true;
53             }
54         }
55     }
56     return false;
57 }
58 
59 int dfs(int now,int flow) {
60     if(now==decc) return flow;
61     int used=0,delat;
62     for(int &i=cur[now];i!=-1;i=e[i].next) {
63         int to=e[i].to;
64         if(e[i].val&&depth[to]==depth[now]+1) {
65             delat=flow-used;
66             delat=dfs(to,min(delat,e[i].val));
67             used+=delat;
68             e[i].val-=delat;
69             e[i^1].val+=delat; 
70             if(used==flow) break;
71         }
72     }
73     if(!used) depth[now]=-1;
74     return used;
75 }
76 
77 int hh() {
78 //    freopen("flyer.in","r",stdin);
79 //    freopen("flyer.out","w",stdout);
80     int x,y,ans=0;
81     read(n);read(m);
82     decc=n+1;
83     fill(head,head+MAXN,-1);
84     for(int i=1;i<=m;++i) add(src,i,1),add(i,src,0);
85     while(scanf("%d%d",&x,&y)) add(x,y,1),add(y,x,0);
86     for(int i=m+1;i<=n;++i) add(i,decc,1),add(decc,i,0);
87     while(bfs()) ans+=dfs(src,INF);
88     printf("%d\n",ans);
89 /*    for(int i=2;i<=tot;i+=2) {   // 输出方案 逆向边有流量则有连边 
90         if(e[i].to!=src&&e[i].to!=decc&&e[i^1].to!=src&&e[i^1].to!=decc) 
91           if(e[i^1].val) printf("%d %d\n",e[i].to,e[i^1].to); 
92     }*/
93     return 0;
94 }
95 
96 int sb=hh();
97 int main() {;}

 1 #include <cstdio>
 2 #include <cstring>
 3 
 4 const int MAXN=110;
 5 
 6 int n,m;
 7 
 8 int map[MAXN][MAXN],mark[MAXN];
 9 
10 bool vis[MAXN];
11 
12 bool find(int x) {
13     for(int i=m+1;i<=n;++i) {
14         if(map[x][i]&&!vis[i]) {
15             vis[i]=true; 
16             if(!mark[i]||find(mark[i])) {
17                 mark[i]=x;
18                 return true;
19             }
20         }
21     }
22     return false;
23 }
24 
25 int hh() {
26     freopen("flyer.in","r",stdin);
27     freopen("flyer.out","w",stdout);
28     int x,y,ans=0;
29     scanf("%d%d",&n,&m);
30     while(scanf("%d%d",&x,&y)!=EOF) map[x][y]=1;
31     for(int i=1;i<=m;++i) {
32         memset(vis,false,sizeof vis);
33         if(find(i)) ans++;
34     }
35     printf("%d\n",ans);// 二分图匹配 方案容易输出 自己想吧 
36     return 0;
37 }
38 
39 int sb=hh();
40 int main() {;}