#include <bits/stdc++.h>
using namespace std;
string ans, s;
string table[] = {"", "@afkpuz", "@bglqv.", "@chmrw?", "@dinsx!", "@ejoty "};
int main() {
  while (cin >> s) {
    ans = "";
    if (s.size() % 2 == 1) {
      cout << "NA" << endl;
      continue;
    }
    for (int i = 0; i < s.size(); i += 2) {
      ans += table[s[i + 1] - '0'][s[i] - '0'];
    }
    cout << ans << endl;
  }
}
