#include <cstdio>
#define min(x,y) ((x)<(y)?(x):(y))
#define abs(x) ((x)>0?x:-x)
#define MAXV 1001

using namespace std;

int n,m,s,d,v[MAXV],q[MAXV];
int c[MAXV][MAXV];//capacitate
int f[MAXV][MAXV];//flux

void citire()
{
    freopen("cuplaj.in","r",stdin);
    scanf("%d%d", &n, &m);
    s=0,d=n+1;
    int x,y;
    for (int i=0; i<m; i++)
    {
        scanf("%d%d", &x, &y);
        c[x][y]=1;
        c[0][x]=1;
        c[y][n+1]=1;
    }
    ++n;
}

int bfs()
{
    int p,u,x;
    q[0]=s;
    p=u=0;
    v[s]=1;
    while (p<=u && !v[d])
    {
        x=q[p++];
        for (int i=1; i<=n; i++)
            if (!v[i])
                if (f[x][i]<c[x][i])
                {
                    v[i]=x;
                    q[++u]=i;
                }
                else if (f[i][x]>0)
                {
                    v[i]=-x;
                    q[++u]=i;
                }
    }
    return !v[d];
}

void flux()
{
    int l[MAXV],a,b,lg,V;
    do
    {
        for (int i=1; i<=n; i++)
            v[i]=0;
        if (bfs())
            return;
        l[0]=d;
        lg=0;
        a=b=10000;
        while (l[lg]!=s)
        {
            l[++lg]=abs(v[l[lg-1]]);
            if (v[l[lg-1]]>0)
                a=min(a,c[l[lg]][l[lg-1]]-f[l[lg]][l[lg-1]]);
            else
            if (v[l[lg-1]]<0)
                b=min(b,f[l[lg-1]][l[lg]]);
        }
        V=min(a,b);
        for (int i=lg; i>0; i--)
            if (v[l[i-1]]>0)
                f[l[i]][l[i-1]]+=V;
            else
                f[l[i-1]][l[i]]-=V;
    }
    while (1);
}

void afisare()
{
    freopen("cuplaj.out","w",stdout);
    int vf=0;
    for (int i=1; i<=n; i++)
        vf+=f[i][d];
    printf("%d\n",vf);
}

int main()
{
    citire();
    flux();
    afisare();
    return 0;
}