#include <bits/stdc++.h>
#include <atcoder/all>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,fma,abm,mmx,avx,avx2")
// url 
#define rep(i,a,b) for(int i=a;i<b;i++)
#define rrep(i,a,b) for(int i=b-1;i>=a;i--)
#define all(x) (x).begin(),(x).end()
#define pb(x) push_back(x);
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }
typedef long long ll;
typedef long double lld;
using namespace std;
using namespace atcoder;
using mint = static_modint<998244353>;
const ll mod=998244353;
// using mint = static_modint<1000000007>;
//const ll mod=1e9+7;
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
const string zton="0123456789";
const string atoz="abcdefghijklmnopqrstuvwxyz";
const string ATOZ="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const ll inf=(1ll<<60);
// const int inf=(1<<30);
lld dist(lld x1,lld x2,lld y1,lld y2){
    lld res=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
    res=sqrt(abs(res));
    return res;
}
lld arg(lld x,lld y){
    const lld eps=1e-8;
    lld res=0;
    if(abs(x)+abs(y)<=eps)return 0.0;
    else if(abs(x)<=eps){
        if(y>=0.0)return (M_PI/2);
        else return (M_PI/2+M_PI);
    }
    else if(abs(y)<=eps){
        if(x>=0.0)return 0.0;
        else return M_PI;
    }
    res=atan2(abs(y),abs(x));
    if(x<=0&&y>=0)res=(M_PI-res);
    else if(x<=0&&y<=0)res+=(M_PI);
    else if(x>=0&&y<=0)res=(M_PI*2-res);
    return res;
}
ll gcd(ll a,ll b){
    if(a==0||b==0)return a+b;
    ll r;
    r=a%b;
    if(r==0){
        return b;
    }
    else{
        return gcd(b,r);
    }
}
std::ostream &operator<<(std::ostream &dest, __int128_t value) {
    std::ostream::sentry s(dest);
    if (s) {
        __uint128_t tmp = value < 0 ? -value : value;
        char buffer[128];
        char *d = std::end(buffer);
        do {
            --d;
            *d = "0123456789"[tmp % 10];
            tmp /= 10;
        } while (tmp != 0);
        if (value < 0) {
            --d;
            *d = '-';
        }
        int len = std::end(buffer) - d;
        if (dest.rdbuf()->sputn(d, len) != len) {
            dest.setstate(std::ios_base::badbit);
        }
    }
    return dest;
}
__int128 parse128(string &s) {
    __int128 ret = 0;
    for (int i = 0; i < s.length(); i++){
        if ('0' <= s[i] && s[i] <= '9'){
            ret = 10 * ret + s[i] - '0';
        }
    }
    return ret;
}
using l3 = __int128;

bool comp_arg(pair<ll,ll> a,pair<ll,ll> b){
    if(a.second>=0&&b.second<0)return true;
    else if(a.second<0&&b.second>=0)return false;
    if(a.second>=0&&b.second>=0){
        if(a.first>=0&&b.first<0)return true;
    }
    else{
        if(a.first>=0&&b.first<0)return false;
    }
    ll det=a.first*b.second-a.second*b.first;
    if(det>0)return true;
    return false;
}

typedef pair<ll,int> P;
// 2 1
// 1 <==> 2

int main(void){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int N,M;cin >> N >> M;
    int a[M],b[M],c[M],ab[M];
    vector<int> G[N];
    rep(i,0,M){
        cin >> a[i];
        string s;cin >> s;
        cin >> b[i];
        a[i]--;b[i]--;
        ab[i]=a[i]^b[i];

        if(s=="<=/=>"){
            c[i]=1;
        }
        else{
            c[i]=0;
        }
        G[a[i]].pb(i);
        G[b[i]].pb(i);
    }
    // rep(i,0,M){
    //     cout << a[i] << " " << b[i] << " " << c[i] << endl;
    // }
    // return 0;
    int ans=0;
    int col[N];fill(col,col+N,-1);
    rep(i,0,N){
        if(col[i]!=-1)continue;
        col[i]=0;
        int cnt[2]={1,0};
        queue<int> que;
        que.push(i);
        vector<int> v;v.pb(i);
        while(que.size()){
            int from=que.front();
            que.pop();
            for(int id:G[from]){
                int to=ab[id]^from;
                if(col[to]==-1){
                    if(c[id]){
                        col[to]=col[from]^1;
                    }
                    else{
                        col[to]=col[from];
                    }
                    cnt[col[to]]++;
                    que.push(to);
                    v.pb(to);
                }
                else{
                    if(c[id]){
                        if(col[to]==col[from]){
                            cout << "No" << endl;
                            return 0;
                        }
                    }
                    else{
                        if(col[to]!=col[from]){
                            cout << "No" << endl;
                            return 0;
                        }
                    }
                
                }
            }
        }
        if(cnt[0]<cnt[1]){
            for(int id:v){
                col[id]^=1;
            }
        }
        ans+=max(cnt[0],cnt[1]);
    }
    if(ans*2<N){
        cout << "No" << endl;
        return 0;
    }
    cout << "Yes" << endl;
    cout << ans << endl;
    vector<int> v;rep(i,0,N)if(col[i]==0)v.pb(i);
    rep(i,0,ans){
        cout << v[i]+1;
        if(i!=ans-1)cout << " ";
        else cout << endl;
    }
}