#include <bits/stdc++.h>
using namespace std;
int main() {
  char g[42] = {97,  102, 107, 112, 117, 122, 98,  103, 108, 113,
                118, 46,  99,  104, 109, 114, 119, 63,  100, 105,
                110, 115, 120, 33,  101, 106, 111, 116, 121, 32};
  string s, a;
  while (cin >> s, !cin.eof()) {
    a = "";
    for (int i = 0; i < s.size(); i += 2) {
      int l = s[i] - '0', r = s[i + 1] - '0';
      if (s.size() % 2 + l<1 + r<1 + l> 6 + r> 5) {
        a = "NA";
        break;
      }
      a += g[r * 6 + l - 7];
    }
    cout << a << endl;
  }
}
