#include <bits/stdc++.h>
#define ll long long
using namespace std;
const int N = 110;
set<int> adj[N];
short int vst[N];
string s[N];
int p[N];
char ch[26];
vector<int> topo;
bool cycle = 0;
void dfs(int u);
int main (int argc, char const *argv[]) {
ios_base::sync_with_stdio(0);
cin.tie(0);
int n; cin >> n;
for(int i = 1; i <= n; ++i) cin >> s[i];
for(int i = 1; i <= n; ++i) cin >> p[i];
memset(ch, 0, sizeof(ch));
vector<string> arr;
for(int i = 1; i <= n; ++i) arr.push_back(s[p[i]]);
for(int i = 0; i < n; ++i){
for(int j = i + 1; j < n; ++j){
bool g = 0;
for(int id = 0; id < arr[i].length() && id < arr[j].length(); ++id){
if(arr[i][id] != arr[j][id]){
adj[arr[i][id] - 'a'].insert(arr[j][id] - 'a');
g = 1;
break;
}
}
if(g) continue;
if(arr[i].length() > arr[j].length()){
cout << "NE";
return 0;
}
}
}
for(int i = 0; i < 26; ++i){
if(vst[i] == 0 && adj[i].size()) dfs(i);
}
if(cycle) {
cout << "NE";
return 0;
}
reverse(topo.begin(), topo.end());
char c = 'a';
for(int x : topo){
ch[x] = c++;
}
cout << "DA\n";
for(int i = 0; i < 26; ++i) cout << (ch[i] == 0 ? c++ : ch[i]);
return 0;
}
void dfs(int u){
if(cycle) return;
if(vst[u] == 2) return;
if(vst[u] == 1){
cycle = 1;
return;
}
vst[u] = 1;
for(int v : adj[u]){
dfs(v);
}
vst[u] = 2;
topo.push_back(u);
}
