#include<iostream> #include<cstring> #include<cstdio> #define inf 0x7fffffff using namespace std; inline int read(){ int x=0,f=1;char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();} return x*f; } struct edge{ int to,next,v; }e[50001]; int n,n1,cnt=1,ans,T=50000,head[50001],h[50001]; void ins(int u,int v,int w){ e[++cnt]=(edge){v,head[u],w};head[u]=cnt; e[++cnt]=(edge){u,head[v],0};head[v]=cnt; } inline bool bfs(){ int q[50001],t=0,w=0; memset(h,-1,sizeof(h)); h[0]=0; while(t<=w){ int now=q[t++]; for(int i=head[now];i;i=e[i].next){ if(e[i].v&&h[e[i].to]==-1){ h[e[i].to]=h[now]+1; q[++w]=e[i].to; } } } if(h[T]==-1)return 0; else return 1; } inline int dfs(int x,int f){ if(x==T)return f; int rest,used=0; for(int i=head[x];i;i=e[i].next){ if(e[i].v&&h[e[i].to]==h[x]+1){ rest=f-used; rest=dfs(e[i].to,min(e[i].v,rest)); e[i].v-=rest; e[i^1].v+=rest; used+=rest; if(used==f)return f; } } if(!used)h[x]=-1; return used; } void dinic(){ while(bfs())ans+=dfs(0,inf); } int main(){ freopen("flyer.in","r",stdin); freopen("flyer.out","w",stdout); n=read();n1=read(); int a,b; while(scanf("%d%d",&a,&b)!=EOF) ins(a,b,1); for(int i=1;i<=n1;i++) ins(0,i,1); for(int i=n1+1;i<=n;i++) ins(i,T,1); dinic(); printf("%d",ans); return 0; }