#include<iostream>
using namespace std;
int main(){
char g[] = {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 << '\n';
}	
}