#include <bits/stdc++.h>
using namespace std;
template <typename T>
using vc = vector<T>;
using pii = pair<long long, long long>;
void xmax(long long& a, long long b) { a = max(a, b); }
void xmin(long long& a, long long b) { a = min(a, b); }
void print(vc<long long>& a, string second) {
  cerr << "prinitng " << second << "\n";
  for (long long i = 0; i < a.size(); i++) {
    cerr << a[i] << " ";
  }
  cerr << endl;
}
map<pair<char, char>, vc<char> > zur;
set<char> contract(string& second, long long i, long long j,
                   vc<vc<set<char> > >& dp) {
  if (dp[i][j].size() > 0) return dp[i][j];
  if (i == j) {
    dp[i][j].insert(second[i]);
    return dp[i][j];
  }
  set<char> pos;
  for (long long k = i; k < j; k++) {
    set<char> cur1 = contract(second, i, k, dp);
    set<char> cur2 = contract(second, k + 1, j, dp);
    for (auto l : cur1) {
      for (auto h : cur2) {
        for (auto p : zur[{l, h}]) pos.insert(p);
      }
    }
  }
  if (pos.size() == 0) pos.insert('.');
  return dp[i][j] = pos;
}
long long find_min(long long n, long long m, long long i, long long j,
                   vc<vc<long long> >& dp, vc<vc<set<char> > >& dp1,
                   vc<vc<set<char> > >& dp2) {
  if (i == n && j == m) return 0;
  if (i == n && j != m) return -1;
  if (j == m && i != n) return -1;
  if (dp[i][j] != 0) return dp[i][j];
  long long mini = -2;
  for (long long k = i; k < n; k++) {
    for (long long h = j; h < m; h++) {
      for (auto p : dp1[i][k]) {
        if (p == '.') continue;
        if (dp2[j][h].find(p) != dp2[j][h].end()) {
          long long cur = find_min(n, m, k + 1, h + 1, dp, dp1, dp2);
          if (mini == -2 && cur != -1) mini = cur;
          if (cur != -1) xmin(mini, cur);
          break;
        }
      }
    }
  }
  assert(mini + 1 != 0);
  return dp[i][j] = mini + 1;
}
long long find_all_contractions(string second, string t) {
  long long n = second.size();
  vc<vc<set<char> > > dp1(n + 1, vc<set<char> >(n + 1));
  contract(second, 0, n - 1, dp1);
  long long m = t.size();
  vc<vc<set<char> > > dp2(m + 1, vc<set<char> >(m + 1));
  contract(t, 0, m - 1, dp2);
  vc<vc<long long> > dp(n + 1, vc<long long>(m + 1, 0));
  return find_min(n, m, 0, 0, dp, dp1, dp2);
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  string second, t;
  cin >> second >> t;
  long long n;
  cin >> n;
  zur.clear();
  for (long long i = 0; i < n; i++) {
    char b, c, d;
    cin >> b >> c >> c >> c >> d;
    zur[{c, d}].push_back(b);
  }
  long long mini = find_all_contractions(second, t);
  cout << mini << "\n";
}
