tioj 1209

/*




                Draw something someday
                But I don't know what to draw咩噗




*/
using namespace std;
#include <vector>
#include <queue>
#include <algorithm>
#include <cmath>
#include <utility>
#include <bitset>
#include <set>
#include <string>
#include <stack>
#include <iomanip>
#include <map>

#define pb push_back
#define pii pair<int,int>
#define F first
#define S second
#define LL long long
#define mid (LB+RB)/2
#define iter(x) x.begin(),x.end()

/*
yungyao so weeeeeeeeeeeeeeeeeeeeeeeeeeak
8e7 so dian
FHVirus so dian
youou so dian
KYW so dian
hubert so dian
jass so dian
tingyu so dian
panda so dian
*/

//IO
#include <iostream>
#define theyRSOOOOOOOOODIAN ios_base::sync_with_stdio(false),cin.tie(0);
#define endl '\n'

//workspace

bitset <100100> vis,color;
vector <int> graph[100100];
bool is_bipartite; //bipartite是二分的意思

inline void init(int n){
    is_bipartite = true;
    vis.reset();
    color.reset();
    for (int i=1;i<=n;++i)
        graph[i].clear();
}

void dfs (int x,bool col){
    color[x] = col;
    vis[x] = true;

    for (auto i:graph[x]){
        if (vis[i]){
            if (col == color[i]){
                is_bipartite = false;
                return;
            }
        }
        else{
            dfs(i,!col);
        }
    }
}

inline void solve(int n,int m){
    init(n);

    while (m--){
        int u,v;

        cin >> u >> v;
        graph[u].pb(v);
        graph[v].pb(u);
    }

    for (int i=1;i<=n;++i){
        if (!vis[i])
            dfs(i,0);

        if (!is_bipartite)
            break;
    }

    cout << (is_bipartite ? "Yes\n" : "No\n");
}

int main(){
    theyRSOOOOOOOOODIAN
    for (int n,m;cin >> n >> m && (n || m);) solve(n,m);
    return 0;
}