#define _USE_MATH_DEFINES
 
#include <iostream>
#include <iomanip>
 
#include <algorithm>
#include <cmath>
 
#include <string>
//#include <array>
#include <list>
#include <queue>
#include <vector>
#include <complex>
#include <set>
#include <map>
 
/////////
#define REP(i, x, n) for(int i = x; i < n; i++)
#define rep(i,n) REP(i,0,n)
#define P(p) cout<<(p)<<endl;
 
#define PII pair<int,int>
/////////
typedef long long LL;
typedef long double LD;
/////////
using namespace::std;
/////////

int main(void){
    std::cin.tie(0); 
    std::ios::sync_with_stdio(false);
    std::cout << std::fixed;//
    //cout << setprecision(10);//
	
	int N,K;cin>>N>>K;

	int s[100],s2[100];
	rep(i,N)s[i]=i;
	int X,Y;
	rep(i,K){
		cin>>X>>Y;
		swap(s[X-1],s[Y-1]);
	}
	
	int Now[100];
	int Next[100];
	rep(i,N){
		Now[i] = i;
	}
	rep(i,N){
		s2[i] = s[ s[i] ];
	}
	int count = 0;
	bool flag;
	do{
		++count;
		flag = true;
		rep(i,N){
			Next[i] = Now[ s[i] ];
			if( i != Next[i]){
				flag = false;
				break;
			}
		}
		if(flag == false){
			++count;
			flag = true;
			rep(i,N){
				Next[i] = Now[ s2[i] ];
				if(Next[i] != i)flag =false;
			}
		}
		//check
		rep(i,N){
			Now[i] = Next[i];
		}
	}while(flag==false);
	P(count);
    return 0;
}