#include "bits/stdc++.h"
using namespace std;

#define DEBUG(x) cout<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cout<<#v<<":";for(int i=0;i<v.size();i++) cout<<" "<<v[i]; cout<<endl

typedef long long ll;
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
const int inf = 1000000001;
const ll INF = 1e16;
#define MOD 1000000007
#define mod 1000000009
#define pi 3.14159265358979323846
#define Sp(p) cout<<setprecision(15)<<fixed<<p<<endl;
int dx[4] = { 1,0,-1,0 }, dy[4] = { 0,1,0,-1 };

int main() {
	int n, k, i, j;
	cin >> n >> k;
	vi x(k), y(k);
	for (i = 0; i < k; i++) {
		cin >> x[i] >> y[i];
	}
	vi a(n);
	for (i = 1; i <= n; i++) {
		int temp = i;
		for (j = 0; j < k; j++) {
			if (x[j] == temp) {
				temp = y[j];
			}
			else if (y[j] == temp) {
				temp = x[j];
			}
		}
		a[temp-1] = i;
	}
	//DEBUG_VEC(a);
	ll cnt = 1;
	vi b = a;
	sort(b.begin(), b.end());
	vi pre = b, now = a;
	while (now != b) {
		pre = now;
		for (i = 0; i < n; i++) {
			now[i] = pre[a[i] - 1];
		}
		cnt++;
	}
	cout << cnt << endl;
}