#include using namespace std; #define FOR(i,a,b) for(int i=(a);i<(b);++i) #define REP(i,n) FOR(i,0,n) #define ALL(v) begin(v),end(v) template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } using ll = long long; using pii = pair; constexpr ll INF = 1ll<<30; constexpr ll longINF = 1ll<<60; constexpr ll MOD = 1000000007; constexpr bool debug = false; //---------------------------------// int main() { int N, M; vector S; cin >> N; REP(i, N) { string s; cin >> s; S.emplace_back(s); } cin >> M; REP(i, M) { string s; cin >> s; S.emplace_back(s); } vector nex(26, -1), indeg(26), exist(26); REP(i, N + M) for (char c : S[i]) exist[c - 'A'] = true; REP(i, N + M) FOR(j, 1, S[i].size()) { const char u = S[i][j - 1] - 'A'; const char v = S[i][j] - 'A'; if (nex[u] != -1) continue; nex[u] = v; ++indeg[v]; } int c = -1; REP(i, 26) { if (exist[i] && indeg[i] == 0) { if (c != -1) { puts("-1"); return 0; } c = i; } } for (; c != -1; c = nex[c]) putchar(c + 'A'); puts(""); }