#include<bits/stdc++.h>
#include <atcoder/all>
using namespace std;using namespace atcoder;using vst = vector<string>;using ll = long long;
using ld = long double;using pll = pair<ll,ll>;using vll = vector<ll>;using vvll = vector<vll>;
using vpll = vector<pll>;
#define rep(i, n) for (ll i = 0; i < n; i++)
#define repp(i,k,n) for (ll i = k; i < n; i++)
#define per(i,s,e) for(ll i = s; i >= e; i--)
#define all(v) v.begin(),v.end()
#define no() {cout << "No" << endl; return 0;}
#define yes(){cout << "Yes" << endl;return 0;}
#define yesno(a) a ? cout << "Yes" << endl : cout << "No" << endl
#define YESNO(a) a ? cout << "YES" << endl : cout << "NO" << endl
#define MODD 998244353LL
#define MOD 1000000007LL
#define UNOmap unordered_map
#define UNOset unordered_set
#define ASC(T) T,vector<T>,greater<T>
#define join(G,a,b) G[a].push_back(b);G[b].push_back(a);
#define PB(a,b) a.push_back(b)
template<class... T>void in(T&... a){(cin >> ... >> a);}
template<class T, class... Ts>void out(const T& a, const Ts&... b){cout << a;((cout << ' ' <<  b), ...);cout << '\n';}
void vin(vll &v){for(ll i = 0; i < (ll)v.size(); i++)in(v[i]);}
void vout(vll &v){for(ll i = 0; i < (ll)v.size(); i++) cout << v[i] << ' ';cout << "\n";}
ll INF = 1LL << 62;

// #include<boost/multiprecision/cpp_int.hpp>
// using namespace boost::multiprecision;

// using mint = modint998244353;
// using mint = modint1000000007;
// using mint = modint;


// cout << fixed << setprecision(15);
//----------------------------------------------



int main(){
  ll N,M;
  in(N,M);
  vvll G(N);
  rep(i,M){
    ll a,b;
    in(a,b);
    a--;
    b--;
    join(G,a,b);
    
  }
  
  vll color(N,-1);
  bool ok = true;
  rep(v,N){
    if(color[v] != -1) continue;
    if(ok == false) break;
    queue<ll> Q;
    Q.push(v);
    color[v] = 0;
    
    while(!Q.empty()){
      ll x = Q.front();
      Q.pop();
      for(auto nx : G[x]){
        if(color[nx] != -1){
          if(color[nx] == color[x]) {
            ok = false;
          }
          continue;
        }
        color[nx] = 1 - color[x];
        Q.push(nx);
      }
    }
  }
  
  yesno(ok);
}