1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<fstream>
 5 #define cin fin
 6 #define cout fout
 7 #define maxn 1000
 8 using namespace std;
 9 int head[maxn],next[maxn],point[maxn],now,visit[maxn];
10 int match[maxn];
11 ofstream fout ("flyer.out");
12 ifstream fin ("flyer.in");
13 void add(int x,int y)
14 {
15     next[++now] = head[x];
16     head[x]=now;
17     point[now] = y;
18 }
19 int dfs(int x)
20 {
21     for(int i=head[x];i;i=next[i])
22     {
23         int u = point[i];
24         if(visit[u])continue;
25         visit[u] = 1;
26         if(match[u]==-1 || dfs(match[u]))
27         {
28             match[u] = x;
29             return 1;
30         }
31     }
32     return 0;
33 }
34 int main()
35 {
36     int n,m,ans=0,x,y;
37     cin>>n>>m;
38     while(cin>>x>>y)
39     {
40         add(x,y);
41     }
42     memset(match,-1,sizeof(match));
43     for(int i=1;i<=m;i++)
44     {
45         memset(visit,0,sizeof(visit));
46         if(dfs(i))ans++;
47     }
48     cout<<ans<<endl;
49     return 0;
50 }