#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
#define drep(i, cc, n) for (ll i = (cc); i <= (n); ++i)
#define rep(i, n) drep(i, 0, n - 1)
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define fi first
#define se second
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const ll MOD1000000007 = 1000000007;
const ll MOD998244353 = 998244353;
const ll MOD[3] = {999727999, 1070777777, 1000000007};
const ll LINF = 1LL << 60LL;
const int IINF = (1 << 30) - 1;

#include<atcoder/all>
using namespace atcoder;

void solve(){
    ll n, m; cin >> n >> m;
    two_sat ts(n);

    rep(i, m){
        ll x, y;
        cin >> x;
        string e; cin >> e;
        cin >> y;
        x--; y--;

        if(e=="<==>"){
            ts.add_clause(x, true, y, false);
            ts.add_clause(x, false, y, true);
        }

        if(e=="<=/=>"){
            ts.add_clause(x, true, y, true);
            ts.add_clause(x, false, y, false);
        }
    }

    if(!ts.satisfiable()){
        cout << "No" << endl;
        return;
    }

    vector<bool> a = ts.answer();
    ll cnt1 = 0;
    for(ll i=0; i<n; i++) cnt1 += a[i];

    cout << "Yes\n";
    if(cnt1>=(n+1)/2){
        cout << cnt1 << endl;
        vector<ll> ans;
        for(ll i=0; i<n; i++){
            if(a[i]){
                ans.pb(i);
            }
        }

        for(ll i=0; i<cnt1; i++){
            cout << ans[i]+1;
            if(i<cnt1-1) cout << " ";
        }
        cout << endl;
    }else{
        cout << n-cnt1 << endl;
        vector<ll> ans;
        for(ll i=0; i<n; i++){
            if(!a[i]){
                ans.pb(i);
            }
        }
        for(ll i=0; i<n-cnt1; i++){
            cout << ans[i]+1;
            if(i<n-cnt1-1) cout << " ";
        }
        cout << endl;
    }
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    
    int T=1;
    //cin >> T;
    while(T--) solve();
}