#include <bits/stdc++.h>
using namespace std;

using ull = uint64_t;
using ll = int64_t;
using vi = vector<int>;
using vll = vector<ll>;
using vs = vector<string>;
using ld = long double;
using P = pair<ll,ll>;
using G = vector<vector<int>>;

#define LO(...) (void)0
#define debug(x) (void)0

#define reps(i,a,n) for(ll i##_len = (ll)(n), i = (a); i < i##_len; ++i)
#define rep(i,n) reps(i,0,(n))
#define rrep(i,n) reps(i,1,(n)+1)
#define repd(i,n) for(ll i=(n)-1;i>=0;i--)
#define rrepd(i,n) for(ll i=(n);i>=1;i--)

#define inp(i) ll i; cin >> i;
#define inps(s) string s; cin >> s;
#define inpp(p) cin >> (p).first >> (p).second
#define inpv(v,N) vll v(N);rep(i,N)cin>>v[i];
#define inpvs(v,N) vs v(N);rep(i,N)cin>>v[i];
#define all(v) begin(v),end(v)
#define Yes cout<<"Yes\n"
#define No cout<<"No\n"
#define allok(i,N,pred) [&]()->bool{bool allok_=1;rep(i,N)if(!(pred))allok_=0;return allok_;}()
#define anyok(i,N,pred) [&]()->bool{bool anyok_=0;rep(i,N)if(pred)anyok_=1;return anyok_;}()
void YESNO(bool b){cout<<(b?"YES\n":"NO\n");}void yesno(bool b){cout<<(b?"yes\n":"no\n");}void YesNo(bool b){cout<<(b?"Yes\n":"No\n");}

#define SP cout << " "
#define ENDL cout << "\n"
#define setfp cout << fixed << setprecision(16)
template<typename C>void ou(const C&v){cout<<v;}
template<typename C>void ous(const C&v){cout<<v<<" ";}
template<typename C>void oul(const C&v){cout<<v<<"\n";}

template<typename C>void ouv(const C &v){for(auto &&e:v){cout << e;if(&e != &v.back()) cout << ' ';}cout << "\n";}
template<typename C>void ouvadd(const C &v){for(auto &&e:v){cout << e+1;if(&e != &v.back()) cout << ' ';}cout << "\n";}

template<typename T>bool chmax(T &a, const T &b){return a<b?(a=b,1):0;}
template<typename T>bool chmin(T &a, const T &b){return b<a?(a=b,1):0;}

template<typename T>void so(T &a){sort(begin(a),end(a));}
template<typename T,typename C>void so(T &a,C c){sort(begin(a),end(a),c);}
template<typename T>void rso(T &a){sort(rbegin(a),rend(a));}
template<typename T,typename C>void rso(T &a,C c){sort(rbegin(a),rend(a),c);}

constexpr ll INF = 1e18;

#ifndef ATCODER_DSU_HPP
#define ATCODER_DSU_HPP 1

#include <algorithm>
#include <cassert>
#include <vector>

namespace atcoder {

// Implement (union by size) + (path compression)
// Reference:
// Zvi Galil and Giuseppe F. Italiano,
// Data structures and algorithms for disjoint set union problems
struct dsu {
  public:
    dsu() : _n(0) {}
    explicit dsu(int n) : _n(n), parent_or_size(n, -1) {}

    int merge(int a, int b) {
        assert(0 <= a && a < _n);
        assert(0 <= b && b < _n);
        int x = leader(a), y = leader(b);
        if (x == y) return x;
        if (-parent_or_size[x] < -parent_or_size[y]) std::swap(x, y);
        parent_or_size[x] += parent_or_size[y];
        parent_or_size[y] = x;
        return x;
    }

    bool same(int a, int b) {
        assert(0 <= a && a < _n);
        assert(0 <= b && b < _n);
        return leader(a) == leader(b);
    }

    int leader(int a) {
        assert(0 <= a && a < _n);
        if (parent_or_size[a] < 0) return a;
        return parent_or_size[a] = leader(parent_or_size[a]);
    }

    int size(int a) {
        assert(0 <= a && a < _n);
        return -parent_or_size[leader(a)];
    }

    std::vector<std::vector<int>> groups() {
        std::vector<int> leader_buf(_n), group_size(_n);
        for (int i = 0; i < _n; i++) {
            leader_buf[i] = leader(i);
            group_size[leader_buf[i]]++;
        }
        std::vector<std::vector<int>> result(_n);
        for (int i = 0; i < _n; i++) {
            result[i].reserve(group_size[i]);
        }
        for (int i = 0; i < _n; i++) {
            result[leader_buf[i]].push_back(i);
        }
        result.erase(
            std::remove_if(result.begin(), result.end(),
                           [&](const std::vector<int>& v) { return v.empty(); }),
            result.end());
        return result;
    }

  private:
    int _n;
    // root node: -1 * component size
    // otherwise: parent
    std::vector<int> parent_or_size;
};

}  // namespace atcoder

#endif  // ATCODER_DSU_HPP

int main() {
    inp(N);
    inp(M);
    G g;
    g.resize(N);
    atcoder::dsu ds(N*2);
    rep(i,M){
        inp(a);
        inp(b);
        a--,b--;
        g[a].push_back(b);
        g[b].push_back(a);

        ds.merge(a, b+N);
        ds.merge(a+N, b);
    }
    YesNo(allok(i,N,ds.same(i,i+N)));
}