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

typedef long long ll;
typedef vector< int > vi;
typedef vector< vi > vvi;
typedef vector< ll > vl;
typedef vector< vl > vvl;
typedef pair< int, int > pii;
typedef vector< pii > vp;
typedef vector< double > vd;
typedef vector< vd > vvd;
typedef vector< string > vs;

template< class T1, class T2 >
int upmin( T1 &x, T2 v ){
  if( x > v ){
    x = v;
    return 1;
  }
  return 0;
}

template< class T1, class T2 >
int upmax( T1 &x, T2 v ){
  if( x < v ){
    x = v;
    return 1;
  }
  return 0;
}

const int INF = 0x3f3f3f3f;

int N, M;
vp E;

void init(){
  cin >> N >> M;
  E = vp( M );
  for( int i = 0; i < M; ++i )
    cin >> E[ i ].first >> E[ i ].second,
    --E[ i ].first, --E[ i ].second;
}

vi cycle;

void preprocess(){
  vi ed( N );
  for( int i = 0; i < N; ++i )
    ed[ i ] = i;
  for( int i = 0; i < M; ++i )
    swap( ed[ E[ i ].first ], ed[ E[ i ].second ] );
  vi vis( N );
  for( int i = 0; i < N; ++i )
    if( not vis[ i ] ){
      int len = 1;
      for( int u = i; ed[ u ] != i; u = ed[ u ] )
        ++len;
      cycle.emplace_back( len );
    }
}

void solve(){
  if( cycle.empty() )
    cout << 0 << endl, exit( 0 );
  ll ans = 1LL;
  for( int i = 0; i < cycle.size(); ++i )
    ans = ans / __gcd( ans, 1LL * cycle[ i ] ) * cycle[ i ];
  cout << ans << endl;
}

signed main(){
  ios::sync_with_stdio( 0 );
  init();
  preprocess();
  solve();
  return 0;
}