#include <bits/stdc++.h>

#define int long long

using namespace std;
using ll = long long;

void solve();

template<typename ...Args>
void println(Args... args) {
    apply([](auto &&... args) { ((cout << args << ' '), ...); }, tuple(args...));
    cout << '\n';
}

int32_t main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int t = 1;
//    cin >> t;
    for (int tc = 0; tc < t; ++tc) {
        solve();
    }
    return 0;
}

struct DSU {
    vector<int> sz, p;

    explicit DSU(int n) : sz(n, 1), p(n) { iota(p.begin(), p.end(), 0); }

    int get(int x) { return x == p[x] ? x : p[x] = get(p[x]); }

    bool unite(int x, int y) {
        x = get(x), y = get(y);
        if (x == y) return false;
        if (sz[x] > sz[y]) swap(x, y);
        sz[y] += sz[x];
        p[x] = y;
        return true;
    }
};

void solve() {
    int n, m;
    cin >> n >> m;
    DSU dsu(2 * n);
    for (int j = 0; j < m; ++j) {
        int x, y;
        string s;
        cin >> x >> s >> y;
        --x, --y;
        if (s == "<==>") {
            dsu.unite(x, y);
            dsu.unite(x + n, y + n);
        } else if (s == "<=/=>") {
            dsu.unite(x, y + n);
            dsu.unite(x + n, y);
        }
    }
    for (int i = 0; i < n; ++i) {
        if (dsu.get(i) == dsu.get(i + n)) {
            cout << "No\n";
            return;
        }
    }
    vector<int> take(2 * n);
    vector<int> cnt(2 * n);
    for (int i = 0; i < n; ++i) cnt[dsu.get(i)]++;
    for (int i = 0; i < n; ++i) {
        int x = dsu.get(i), y = dsu.get(i + n);
        if (cnt[x] >= cnt[y]) take[x] = 1, take[y] = 0; else take[y] = 1, take[x] = 0;
    }
    vector<int> ans;
    for (int i = 0; i < n; ++i) if (take[dsu.get(i)]) ans.push_back(i + 1);
    cout << "Yes" << '\n';
    cout << ans.size() << '\n';
    for (int x : ans) cout << x << " \n"[x == ans.back()];
}