#include <bits/stdc++.h>
using namespace std;
const int mod = 1000 * 1000 * 1000 + 7;
const int INF = 1000 * 1000 * 1000;
const long long LINF = (long long)INF * INF;
vector<pair<int, int> > adj[30];
int dp[30][30];
void fld(void) {
  for (int i = (1); i < (27); i++) {
    fill(dp[i], dp[i] + 30, INF);
    for (pair<int, int> u : adj[i]) {
      dp[i][u.first] = min(dp[i][u.first], u.second);
    }
    dp[i][i] = 0;
  }
  for (int k = (1); k < (27); k++) {
    for (int i = (1); i < (27); i++) {
      for (int j = (1); j < (27); j++) {
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k][j]);
      }
    }
  }
}
int main(void) {
  string s, t;
  cin >> s >> t;
  int n;
  cin >> n;
  for (int i = (0); i < (n); i++) {
    char ai, bi;
    int wi;
    cin >> ai >> bi >> wi;
    ai -= 'a' - 1;
    bi -= 'a' - 1;
    adj[ai].push_back({bi, wi});
  }
  if (s.size() != t.size()) {
    cout << -1 << endl;
    return 0;
  }
  fld();
  n = s.size();
  vector<int> ans;
  int cost = 0;
  for (int i = (0); i < (n); i++) {
    int minc = -1;
    s[i] -= 'a' - 1;
    t[i] -= 'a' - 1;
    int md = 0x7f7f7f7f;
    for (int j = (1); j < (27); j++) {
      int dist = dp[s[i]][j] + dp[t[i]][j];
      if (dist < md) {
        md = dist;
        minc = j;
      }
    }
    if (md >= INF) {
      cout << -1 << endl;
      return 0;
    }
    cost += md;
    ans.push_back(minc);
  }
  cout << cost << endl;
  for (int x : ans) {
    char c = (char)x;
    c += 'a' - 1;
    cout << c;
  }
  cout << endl;
  return 0;
}
