#include <iostream>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <iomanip>
#include <cassert>
using namespace std;

#define GET_ARG(a,b,c,F,...) F
#define REP3(i,s,e) for (i = s; i <= e; i++)
#define REP2(i,n) REP3 (i,0,(int)(n)-1)
#define REP(...) GET_ARG (__VA_ARGS__,REP3,REP2) (__VA_ARGS__)
#define RREP3(i,s,e) for (i = s; i >= e; i--)
#define RREP2(i,n) RREP3 (i,(int)(n)-1,0)
#define RREP(...) GET_ARG (__VA_ARGS__,RREP3,RREP2) (__VA_ARGS__)
#define DEBUG(x) cerr << #x ": " << x << endl

vector<int> e[20000];
map<pair<set<int>,int>,bool> memo;

bool dfs(int v, set<int> s) {
    if (memo.count({s,v})) return memo[{s,v}];
    set<int> tmp = s;
    tmp.insert(v);
    bool ret = false;
    for (auto x: e[v]) {
        if (x == 0 && tmp.size() == 5) ret = true;
        if (!tmp.count(x) && tmp.size() < 5) ret |= dfs(x,tmp);
    }
    return memo[{s,v}] = ret;
}

int main(void) {
    int i, n, m;
    scanf("%d%d",&n,&m);
    REP (i,m) {
        int a, b;
        scanf("%d%d",&a,&b);
        a--; b--;
        e[a].push_back(b);
        e[b].push_back(a);
    }
    if (dfs(0,{}))
        puts("YES");
    else
        puts("NO");
    return 0;
}