#include <fstream>
#include <cstring>
using namespace std;

ifstream cin("bacon.in");
ofstream cout("bacon.out");

int x;
char s[100001];

int main()
{
    cin >> x;

    if (x == 1)
    {
        cin >> s;

        for (int i = 0; i < strlen(s); i++)
        {
            int num = 5;
            int a = (int)s[i] - 65;
            int t[6];
            for (int z = 1; z <= 5; z++)
                t[z] = 0;

            while (a)
            {
                t[num] = a % 2;
                a /= 2;
                num--;
            }

            for (int i = 1; i <= 5; i++)
            {
                if (t[i] == 0)
                    cout << "A";
                else
                    cout << "B";
            }
        }
    }
    else
    {
        cin >> s;

        for (int i = 0; i < strlen(s); i += 5)
        {
            int a = 0;
            int t[5];
            for (int z = 1; z <= 5; z++)
            {
                if (s[i + z] == 'A')
                    t[z] = 0;
                else
                    t[z] = 1;

                a = a * 2 + t[z];
            }

            cout << (char)(a + 65);
        }
    }
}