#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

ll gcd(ll a,ll b){
	if(!b) return a;
	return gcd(b,a%b);
}

ll lcm(ll a,ll b){
	return a/gcd(a,b)*b;
}

int n,m;
vi a;

int main(){
	cin>>n>>m;
	a=vi(n);
	for(int i=0;i<n;i++) a[i]=i;
	for(int i=0;i<m;i++){
		int x,y;
		cin>>x>>y;
		swap(a[x-1],a[x]);
	}
	ll t=1;
	vi b(n);
	for(int i=0;i<n;i++) if(!b[i]){
		ll A=0,v=i;
		while(!b[v]){
			b[v]=1;
			v=a[v];
			A++;
		}
		t=lcm(t,A);
	}
	cout<<t<<endl;
}