#include <bits/stdc++.h>

using namespace std;

using int64 = long long;
const int mod = 1e9 + 7;


const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;


template< typename T1, typename T2 >
ostream &operator<<(ostream &os, const pair< T1, T2 > &p) {
  os << p.first << " " << p.second;
  return os;
}

template< typename T1, typename T2 >
istream &operator>>(istream &is, pair< T1, T2 > &p) {
  is >> p.first >> p.second;
  return is;
}

template< typename T >
ostream &operator<<(ostream &os, const vector< T > &v) {
  for(int i = 0; i < (int) v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template< typename T >
istream &operator>>(istream &is, vector< T > &v) {
  for(T &in : v) is >> in;
  return is;
}

template< typename T1, typename T2 >
inline bool chmax(T1 &a, T2 b) { return a < b && (a = b, true); }

template< typename T1, typename T2 >
inline bool chmin(T1 &a, T2 b) { return a > b && (a = b, true); }

template< typename T = int64 >
vector< T > make_v(size_t a) {
  return vector< T >(a);
}

template< typename T, typename... Ts >
auto make_v(size_t a, Ts... ts) {
  return vector< decltype(make_v< T >(ts...)) >(a, make_v< T >(ts...));
}

template< typename T, typename V >
typename enable_if< is_class< T >::value == 0 >::type fill_v(T &t, const V &v) {
  t = v;
}

template< typename T, typename V >
typename enable_if< is_class< T >::value != 0 >::type fill_v(T &t, const V &v) {
  for(auto &e : t) fill_v(e, v);
}

template< typename F >
struct FixPoint : F {
  FixPoint(F &&f) : F(forward< F >(f)) {}

  template< typename... Args >
  decltype(auto) operator()(Args &&... args) const {
    return F::operator()(*this, forward< Args >(args)...);
  }
};

template< typename F >
inline decltype(auto) MFP(F &&f) {
  return FixPoint< F >{forward< F >(f)};
}


template< int char_size >
struct TrieNode {
  int nxt[char_size];

  int exist;
  vector< int > accept;

  TrieNode() : exist(0) {
    memset(nxt, -1, sizeof(nxt));
  }
};

template< int char_size, int margin >
struct Trie {
  using Node = TrieNode< char_size >;

  vector< Node > nodes;
  int root;

  Trie() : root(0) {
    nodes.push_back(Node());
  }

  void update_direct(int node, int id) {
    nodes[node].accept.push_back(id);
  }

  void update_child(int node, int child, int id) {
    ++nodes[node].exist;
  }

  void add(const string &str, int str_index, int node_index, int id) {
    if(str_index == str.size()) {
      update_direct(node_index, id);
    } else {
      const int c = str[str_index] - margin;
      if(nodes[node_index].nxt[c] == -1) {
        nodes[node_index].nxt[c] = (int) nodes.size();
        nodes.push_back(Node());
      }
      add(str, str_index + 1, nodes[node_index].nxt[c], id);
      update_child(node_index, nodes[node_index].nxt[c], id);
    }
  }

  void add(const string &str, int id) {
    add(str, 0, 0, id);
  }

  void add(const string &str) {
    add(str, nodes[0].exist);
  }

  void query(const string &str, const function< void(int) > &f, int str_index, int node_index) {
    for(auto &idx : nodes[node_index].accept) f(idx);
    if(str_index == str.size()) {
      return;
    } else {
      const int c = str[str_index] - margin;
      if(nodes[node_index].nxt[c] == -1) return;
      query(str, f, str_index + 1, nodes[node_index].nxt[c]);
    }
  }

  void query(const string &str, const function< void(int) > &f) {
    query(str, f, 0, 0);
  }

  int count() const {
    return (nodes[0].exist);
  }

  int size() const {
    return ((int) nodes.size());
  }
};

template< int char_size, int margin >
struct AhoCorasick : Trie< char_size + 1, margin > {
  using Trie< char_size + 1, margin >::Trie;

  const int FAIL = char_size;
  vector< int > correct;

  void build(bool heavy = true) {
    correct.resize(this->size());
    for(int i = 0; i < this->size(); i++) {
      correct[i] = (int) this->nodes[i].accept.size();
    }
    queue< int > que;
    for(int i = 0; i <= char_size; i++) {
      if(~this->nodes[0].nxt[i]) {
        this->nodes[this->nodes[0].nxt[i]].nxt[FAIL] = 0;
        que.emplace(this->nodes[0].nxt[i]);
      } else {
        this->nodes[0].nxt[i] = 0;
      }
    }
    while(!que.empty()) {
      auto &now = this->nodes[que.front()];
      int fail = now.nxt[FAIL];
      correct[que.front()] += correct[fail];
      que.pop();
      for(int i = 0; i < char_size; i++) {
        if(~now.nxt[i]) {
          this->nodes[now.nxt[i]].nxt[FAIL] = this->nodes[fail].nxt[i];
          if(heavy) {
            auto &u = this->nodes[now.nxt[i]].accept;
            auto &v = this->nodes[this->nodes[fail].nxt[i]].accept;
            vector< int > accept;
            set_union(begin(u), end(u), begin(v), end(v), back_inserter(accept));
            u = accept;
          }
          que.emplace(now.nxt[i]);
        } else {
          now.nxt[i] = this->nodes[fail].nxt[i];
        }
      }
    }
  }

  map< int, int > match(const string &str, int now = 0) {
    map< int, int > result;
    for(auto &c : str) {
      now = this->nodes[now].nxt[c - margin];
      for(auto &v : this->nodes[now].accept) result[v] += 1;
    }
    return result;
  }

  pair< int64_t, int > move(const char &c, int now = 0) {
    now = this->nodes[now].nxt[c - margin];
    return {correct[now], now};
  }

  pair< int64_t, int > move(const string &str, int now = 0) {
    int64_t sum = 0;
    for(auto &c : str) {
      auto nxt = move(c, now);
      sum += nxt.first;
      now = nxt.second;
    }
    return {sum, now};
  }
};


int N, M, K;
string from[250], to[250];
string seasonword[30];
unordered_map< int, int > dp[21][500][2];

int main() {
  while(cin >> N >> M >> K, N) {

    vector< int > g[500];
    vector< string > nums;

    for(int i = 0; i < N; i++) {
      cin >> from[i] >> to[i];
      nums.push_back(from[i]);
      nums.push_back(to[i]);
    }
    for(int i = 0; i < K; i++) {
      cin >> seasonword[i];
    }

    sort(begin(nums), end(nums));
    nums.erase(unique(begin(nums), end(nums)), end(nums));
    for(int i = 0; i < N; i++) {
      int u = lower_bound(begin(nums), end(nums), from[i]) - begin(nums);
      int v = lower_bound(begin(nums), end(nums), to[i]) - begin(nums);
      g[u].push_back(v);
    }

    AhoCorasick< 26, 'a' > aho;
    for(int i = 0; i < K; i++) aho.add(seasonword[i]);
    aho.build();

    for(int i = 0; i < nums.size(); i++) {
      if(nums[i].size() > M) continue;
      auto get = aho.move(nums[i]);
      if(get.first > 1) continue;
      ++dp[nums[i].size()][i][get.first][get.second];
    }
    for(int i = 1; i < M; i++) {
      for(int j = 0; j < nums.size(); j++) {
        for(int k = 0; k < 2; k++) {
          for(auto &v : dp[i % 21][j][k]) {
            for(auto &t : g[j]) {
              if(i + nums[t].size() > M) continue;
              auto get = aho.move(nums[t], v.first);
              if(k + get.first > 1) continue;
              (dp[(i + nums[t].size()) % 21][t][k + get.first][get.second] += v.second) %= mod;
            }
          }
          dp[i % 21][j][k].clear();
        }
      }
    }
    int ret = 0;
    for(int j = 0; j < nums.size(); j++) {
      for(auto &v : dp[M % 21][j][1]) (ret += v.second) %= mod;
    }
    cout << ret << endl;


    for(int i = 0; i < 21; i++) {
      for(int j = 0; j < nums.size(); j++) {
        for(int k = 0; k < 2; k++) dp[i][j][k].clear();
      }
    }
  }
}


Measured memory_bytes: 7400