#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cmath>
#include <cstring>
#include <algorithm>
#include <vector>
#include <queue>
using namespace std;
typedef long long ll;
const int maxn=100010;

vector<int> G[maxn];
int vis[maxn],deg[maxn];
queue<int> q;

int main()
{
    freopen("asm_game.in","r",stdin);
    freopen("asm_game.out","w",stdout);
    int n,m,u,v;scanf("%d%d",&n,&m);
    while(m--)
    {
        scanf("%d%d",&u,&v);
        G[u].push_back(v);deg[u]++;
        G[v].push_back(u);deg[v]++;
    }
    int sum=0;
    for(int i=1;i<=n;i++)
    {
        sum^=i;
        if(deg[i]<3)
        {
            q.push(i);
            vis[i]=1;sum^=i;
            //printf("%d\n",i);
        }
    }
    while(!q.empty())
    {
        u=q.front();q.pop();
        int len=G[u].size();
        for(int i=0;i<len;i++)
        {
            int v=G[u][i];
            if(!vis[v])
            {
                deg[v]--;
                if(deg[v]<3)
                {
                    q.push(v);
                    vis[v]=1;sum^=v;
                }
            }
        }
    }
    printf("%d\n",sum);
    return 0;
}