#include <bits/stdc++.h>
using namespace std;
int main() {
  string a;
  while (cin >> a) {
    cout << a.length() << endl;
    if (a.length() % 2 == 1) {
      cout << "NA" << endl;
      continue;
    }
    string t = "";
    bool p = true;
    for (int b = 0; b < a.length(); b += 2) {
      if (a[b] > '6' || a[b] < '1' || a[b + 1] > '5' || a[b + 1] < '1') {
        cout << "NA" << endl;
        p = false;
        break;
      }
      int s = (a[b] - 49) * 5 + (a[b + 1] - 49) + 97;
      if (s < 123)
        t += (char)s;
      else {
        switch (s) {
          case 123:
            t += '.';
            break;
          case 124:
            t += '?';
            break;
          case 125:
            t += '!';
            break;
          case 126:
            t += ' ';
            break;
        }
      }
    }
    if (p) cout << t << endl;
  }
}
