1 #include<vector>
 2 #include<iostream>
 3 using namespace std;
 4 #include<cstdio>
 5 #include<cstring>
 6 #define N 110
 7 bool visit[N]={false};
 8 int n,n1;
 9 struct Edge{
10     int v,last;
11 };
12 int m=-1,head[N],Link[N];
13 vector<Edge>edge;
14 void add_edge(int u,int v)
15 {
16     Edge e;
17     e.v=v;
18     e.last=head[u];
19     head[u]=++m;
20     edge.push_back(e);
21 }
22 void input()
23 {
24     scanf("%d%d",&n,&n1);
25     int u,v;
26     while(scanf("%d%d",&u,&v)==2)
27     {
28         add_edge(u,v);
29     }
30 }
31 bool xylfind(int k)
32 {
33     for(int l=head[k];l!=-1;l=edge[l].last)
34     {
35         if(!visit[edge[l].v])
36         {
37             visit[edge[l].v]=true;
38             if(!Link[edge[l].v]||xylfind(Link[edge[l].v]))
39             {
40                 Link[edge[l].v]=k;
41                 return true;
42             }
43         }
44     }
45     return false;
46 }
47 int main()
48 {
49     freopen("flyer.in","r",stdin);
50     freopen("flyer.out","w",stdout);
51     memset(head,-1,sizeof(head));
52     input();
53     int ans=0;
54     for(int i=1;i<=n1;++i)
55     {
56         memset(visit,false,sizeof(visit));
57         if(xylfind(i)) ans++;
58     }
59     printf("%d\n",ans);
60     fclose(stdin);
61     fclose(stdout);
62     return 0;
63 }