#include <stdio.h>
#include <stdlib.h>
#define N 10100
#define C 6000000
#define MIN(a,b) (((a)<(b))?(a):(b))

typedef struct hrana
{
	short a,b;
};

hrana hr[C];
int ind[N];
int n,m;
int cislo[N],min[N],poc[N];
int cis;

int hr_cmp(const void *a, const void *b)
{
	hrana *va = (hrana *)a;
	hrana *vb = (hrana *)b;
	if (va->a > vb->a) return 1;
	if (va->a < vb->a) return -1;	
	if (va->b > vb->b) return 1;	
	return -1;
}

void bt(int v)
{
	int i,dd,w;
	cislo[v]=min[v]=cis++;
	
	dd=ind[v+1];
	for ( i=ind[v]; i<dd; i++ )
	{
		w=hr[i].b;
		if (cislo[w]==-1) 
		{
			bt(w);
			if (min[w] >= cislo[v]) 
				poc[v]++; 
		}
		min[v]=MIN(min[v],min[w]);
	}
}

int main()
{
	int a,b;
	int p1,i;
	int komp,best;

	while (1)
	{
		scanf("%d %d", &n, &m);
		if (!n && !m) break;
		for ( i=0; i<m; i++ ) 
		{
			scanf("%d %d", &a, &b);
			hr[2*i].a=a; hr[2*i].b=b;
			hr[2*i+1].a=b; hr[2*i+1].b=a;						
		}

		m=2*m;
		qsort(hr, m, sizeof(hr[0]), hr_cmp);
		ind[0]=0; p1=0;
		
		for ( i=0; i<m; i++ ) 
		{
			while (hr[i].a!=p1 && p1<n) 
			{
				p1++; ind[p1]=i;
			}
		}
		
		while (p1<n) ind[++p1]=m;		

		cis=0; 
		for ( i=0; i<n; i++ ) {cislo[i]=-1; poc[i]=0;}
		komp=0;

		for ( i=0; i<n; i++ ) 
		{
			if (cislo[i]==-1)
			{
				komp++;
				bt(i);
				poc[i]--;
			}
		}		

		best=0;
		for ( i=0; i<n; i++ ) if (poc[i]>best) best=poc[i];
		printf("%d\n", best+komp);
	}
	
	return 0;
}