#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
using ll=long long;
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
template<class T> bool chmax(T &a, T b){if (a < b){a = b;return true;} else return false;}
template<class T> bool chmin(T &a, T b){if (a > b){a = b;return true;} else return false;}

struct UnionFind {
private:
    vector<int> par, siz;

public:
    UnionFind(int n) : par(n, -1), siz(n, 1) {}
    int find(int x) {
        if (par[x] == -1) return x;
        else {
            par[x] = find(par[x]);
            return par[x];
        }
    }
    bool same(int x, int y) {
        return find(x) == find(y);
    }
    int size(int x) {
        return siz[find(x)];
    }
    bool merge(int x, int y) {
        x = find(x);
        y = find(y);
        if (x == y) return false;
        if (siz[x] < siz[y]) swap(x, y);
        siz[x] += siz[y];
        par[y] = x;
        return true;
    }
};

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N,M;
    cin>>N>>M;
    vector<int>P(N,-1);
    UnionFind uf(N);
    bool flag=true;
    for(int i=0;i<M;i++){
        int a,b;
        cin>>a>>b;
        a--;
        b--;
        if(P[a]==-1&&P[b]==-1){
            P[a]=0;
            P[b]=1;
            uf.merge(a,b);
        }else if(P[a]==-1){
            P[a]=1-P[b];
            uf.merge(a,b);
        }else if(P[b]==-1){
            P[b]=1-P[a];
            uf.merge(a,b);
        }else{
            if(uf.same(a,b)){
                if(P[a]==P[b]){
                    flag=false;
                }
            }else{
                if(P[a]==P[b]){
                    for(int i=0;i<N;i++){
                        if(uf.same(i,a))P[i]=1-P[i];
                    }
                }
                uf.merge(a,b);
            }
        }
    }
    cout<<(flag?"Yes\n":"No\n");
}