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

typedef long long int ll;
typedef unsigned long long int llu;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pair<int, int> > vii;

#define rrep(i, m, n) for(int i=m; i<n;  i++)
#define erep(i, n)    for(int i=1; i<=n; i++)
#define  rep(i, n)    for(int i=0; i<n;  i++)
#define rrev(i, m, n) for(int i=n-1; i>=m; i--)
#define erev(i, n)    for(int i=n; i>=1; i--)
#define  rev(i, n)    for(int i=n-1; i>=0; i--)
#define EACH(v)       (v).begin(), (v).end()
#define CNT(a, n, x)  (upper_bound(a, a+n, x)-lower_bound(a, a+n, x))
#define minup(m, x)   (m=min(m, x))
#define maxup(m, x)   (m=max(m, x))
#define mp            make_pair

#define INF 1000000000
#define MOD 1000000009
#define EPS 1E-9

#define MAX_N 100
#define MAX_K 1000

int n, k;
int x[MAX_K], y[MAX_K];
int res;
int num[MAX_N];
bool flag;

int main()
{
  cin >> n >> k;
  rep(i, k) cin >> x[i] >> y[i];
  rep(i, k) x[i] -= 1;
  rep(i, k) y[i] -= 1;
  rep(i, n) num[i] = i;

  while(!flag){
    flag = true;
    rep(i, k) swap(num[x[i]], num[y[i]]);
    rep(i, n) flag &= i == num[i];
    res += 1;
  }

  cout << res << endl;

  return 0;
}