#include<iostream>
#include<string>
#include<bits/stdc++.h>
using namespace std;
int main()
{

    int i,n,x,a;
    string str;
    char c;
    while(1)
    {
        cin>>n;
        if (n==0)
        {
            break;
        }
        else
        {
            cin>>str;
            reverse(str.begin(),str.end());
            for (i=0; i<str.size(); i++)
            {
                if (str[i]=='.')
                {
                    a=28;
                    x = (a+n)%28;

                    if (x==28)
                        str[i]='.';
                    else if (x==27)
                        str[i]='_';
                    else
                        str[i] = x+64;
                }
                else if (str[i]=='_')
                {
                    a=27;
                    x = (a+n)%28;
                    if (x==0)
                        str[i]='.';
                    else if (x==28)
                        str[i]='.';
                    else if (x==27)
                        str[i]='_';
                    else
                        str[i] = x+64;
                }
                else
                {
                    c = str[i];
                    a = c-64;
                    x = (a+n)%28;
                    if (x==0)
                        str[i]='.';
                    else if (x==28)
                        str[i]='.';
                    else if (x==27)
                        str[i]='_';
                    else
                        str[i] = x+64;
                }
            }
            cout << str << end1;
            return 0;
        }
    }
}