#include <iostream>
#include <vector>
#include <cstdio>
#include <string>
#include <queue>
#include <algorithm>
#include <cstring>

using namespace std;

typedef long long LL;

#define MAX_N 101
#define MAX_K 1001

int N, K;
int X[MAX_K], Y[MAX_K];

void Input(){

  cin >> N;
  cin >> K;

  for(int i = 0; i < K; i++){
    cin >> X[i] >> Y[i];
  }

}

void ExecAmida(vector<int>& AmidaList){

  for(int k = 0; k < K; k++){
    int x = X[k], y = Y[k];
    x--; y--;
    swap(AmidaList[x], AmidaList[y]);
  }

}

int Solve(){

  vector<int> InitList;
  vector<int> AmidaList;

  for(int i = 1; i <= N; i++){
    InitList.push_back(i);
    AmidaList.push_back(i);
  }

  int ret = 0;

  while(true){

    ret++;
    ExecAmida(AmidaList);

    if(InitList == AmidaList)
      break;

  }

  return ret;

}

int main(){

  Input();

  cout << Solve() << endl;

  return 0;

}