#include <bits/stdc++.h>
using namespace std;
int main() {
  string A;
  string B;
  int n;
  char start, end;
  int w;
  cin >> A >> B >> n;
  int W[26][26];
  int P[26][26];
  for (int i = 0; i < 26; ++i)
    for (int j = 0; j < 26; ++j) W[i][j] = 1e7;
  for (int i = 0; i < 26; ++i) W[i][i] = 0;
  for (int i = 0; i < 26; ++i)
    for (int j = 0; j < 26; ++j) P[i][j] = -1;
  for (int i = 0; i < n; ++i) {
    cin >> start >> end >> w;
    if (w < W[start - 'a'][end - 'a']) {
      W[start - 'a'][end - 'a'] = w;
      P[start - 'a'][end - 'a'] = start - 'a';
    }
  }
  for (int k = 0; k < 26; ++k) {
    for (int i = 0; i < 26; ++i) {
      for (int j = 0; j < 26; ++j)
        if (W[i][j] > W[i][k] + W[k][j]) {
          P[i][j] = P[k][j];
          W[i][j] = W[i][k] + W[k][j];
        }
    }
  }
  int la = A.length();
  int lb = B.length();
  if (la - lb) {
    cout << -1;
    return 0;
  }
  int sum = 0;
  int t, index;
  string ans = "";
  for (int i = 0; i < la; ++i) {
    index = 0;
    t = W[A[i] - 'a'][0] + W[B[i] - 'a'][0];
    for (int j = 1; j < 26; ++j) {
      if (W[A[i] - 'a'][j] + W[B[i] - 'a'][j] < t) {
        t = W[A[i] - 'a'][j] + W[B[i] - 'a'][j];
        index = j;
      }
    }
    ans += (char)(((int)'a') + index);
    sum += t;
  }
  if (sum >= 1e7 || sum < 0) {
    cout << -1;
    return 0;
  } else {
    cout << sum << endl;
    cout << ans;
    return 0;
  }
}
