#include<iostream>
using namespace std;

string convert(long long n){
    string res="";
    while(n>0){
        n--;
        res=char('A'+(n%26))+res;
        n/=26;
    }
    return res;
}
int main(){
    int key;
    cin>>key;
    
    if(key==1){
        long long n;
        if(!(cin>>n)||n<1){
            cout<<"Invalid input";
            return 0;
        }
        cout<<convert(n);
    }
    else if(key==2){
        float f;
        if(!(cin>>n)||n<1){
            cout << "Invalid input";
            return 0;
        }
        cout<<convert(n);
    }
    else if(key==2){
        float f;
        if(!(cin>>f)||f<1.0){
            cout<<"Invalid input";
            return 0;
        }
        cout<<convert((long long)f);
    }
    else {
        cout<<"Invalid input";
    }
    return 0;
}