#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
using namespace std;
int x[100005],y[100005],z[100005];
int main(){
	freopen("asm_game.in","r",stdin);
	freopen("asm_game.out","w",stdout);
	int m,n;
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		cin>>x[i]>>y[i];
		z[x[i]]++;
		z[y[i]]++;
	}
	for(int i=1;i<=n;i++){
		if(z[i]<3&&z[i]!=0){
			z[i]=0;
			for(int o=1;o<=m;o++){
				if(x[o]==i){
					z[y[o]]--;
				}
				if(y[o]==i){
					z[x[o]]--;
				}
			}
			i++;
		}
	}
	int num=0;
	for(int i=1;i<=n;i++){
		if(z[i]>=3){
			num=num xor i;
		}
	}
	cout<<num;
	return 0;
}