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

using namespace std;

inline int read() {
    int op = 1, a = 0; char c = getchar();
    for (; c < '0' || c > '9'; c = getchar()) if (c == '-') op = -1;
    for (; c >= '0' && c <= '9'; c = getchar()) a = a * 10 + c - '0';
    return op * a;
}

const int maxn = 1e5 + 5;
const int maxm = 5e5 + 5;
int n, m;
int Ecnt, head[maxn];
struct Edge { int to, nxt; } e[maxm << 1];
inline void add_edge(int u, int v) {e[++Ecnt] = (Edge) {v, head[u]}; head[u] = Ecnt;}
int deg[maxn]; bool dead[maxn];

int main() {
    freopen("asm_game.in", "r", stdin);
    freopen("asm_game.out", "w", stdout);
    n = read(), m = read();
    for (int i = 1; i <= m; i++) {
        int u = read(), v = read();
        add_edge(u, v), add_edge(v, u);
        deg[u]++, deg[v]++;
    }
    queue<int> que;
    for (int i = 1; i <= n; i++) {
        dead[i] = 0;
        if (deg[i] < 3) que.push(i);
    }
    for (; !que.empty(); ) {
        int u = que.front(); que.pop();
        if (dead[u]) continue;
        dead[u] = 1;
        for (int i = head[u]; i; i = e[i].nxt) {
            int v = e[i].to;
            if (dead[v]) continue;
            if (deg[v] == 3) que.push(v);
            deg[v]--;
        }
    }
    int ans = 0;
    for (int i = 1; i <= n; i++) if (!dead[i]) ans ^= i;
    cout << ans << '\n';
    return 0;
}