#include<iostream>
using namespace std;
int main(){
    char a[7][7] = {"","*abcde","*fghij","*klmno","*pqrst","*uvwxy","*z.?! "};
    string s;
    while(cin>>s){
        if(s.size()%2==1)cout<<"NA"<<endl;
        else{
            for(int i=0;i<s.size();i+=2){
                cout<<a[s[i]-48][s[i+1]-48];

            }
            cout<<endl;
        }
    }
    return 0;
}