#include <bits/stdc++.h>

#define all(x) begin(x), end(x)

using namespace std;
using ll = long long;

map<string, int> mp;

int rs() {
  string s;
  cin >> s;
  if (mp.count(s)) return mp[s];
  return mp[s] = (int) mp.size();
}

const int N = 303;
bool g[N][N];
vector<int> indexes[N][N];

void YES() {
  cout << "Yes\n";
  exit(0);
}

void NO() {
  cout << "No\n";
  exit(0);
}

void solve() {
  int f = rs();
  int t = rs();
  int n;
  cin >> n;

  vector<vector<pair<int, int>>> edges(n);
  vector<bool> used(n);
  for (int i = 0; i < n; i++) {
    auto &v = edges[i];
    int k;
    cin >> k;
    v.resize(k);
    for (auto&[l, r]: v) {
      l = rs();
      r = rs();
      indexes[l][r].push_back(i);
    }
  }

  if (indexes[f][t].empty()) {
    YES();
  }

  vector<int> q = indexes[f][t];

  int sz = (int) mp.size();

  auto fill_edges = [&](int x, int y) {
    auto &v = indexes[x][y];
    for (int &i: v) {
      if (!used[i]) {
        q.push_back(i);
        used[i] = true;
      }
    }
    v.clear();
  };

  auto relax = [&](vector<pair<int, int>> &e) {
    vector<pair<int, int>> cur, rev;
    for (auto[fr, to]: e) {
      cur.emplace_back(fr, to);
      rev.emplace_back(fr, to);
    }

    for (int i = 0; i < int(cur.size()); i++) {
      auto[fr, to] = cur[i];
      for (int nxt = 0; nxt < sz; nxt++) {
        if (g[to][nxt] && !g[fr][nxt]) {
          g[fr][nxt] = true;
          fill_edges(fr, nxt);
          cur.emplace_back(fr, nxt);
        }
      }
    }

    for (int i = 0; i < int(rev.size()); i++) {
      auto[fr, to] = rev[i];
      for (int pre = 0; pre < sz; pre++) {
        if (g[pre][fr] && !g[pre][to]) {
          g[pre][to] = true;
          fill_edges(pre, to);
          rev.emplace_back(pre, to);
        }
      }
    }
  };

  for (int i = 0; i < int(q.size()); i++) {
    int v = q[i];
    used[v] = true;
    vector<pair<int, int>> e;
    for (auto[x, y]: edges[v]) {
      if (!g[x][y]) {
        g[x][y] = true;
        fill_edges(x, y);
        e.emplace_back(x, y);
      }
    }
    relax(e);
  }

  for (int i = 0; i < sz; i++) {
    for (int j = 0; j < sz; j++) {
      if (g[i][j] && g[j][i] && i != j) {
        NO();
      }
    }
  }

  YES();
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  solve();
}