#include <iostream>
#include <fstream>
#include <string>

using namespace std;

#define FIN "lampa.in"
#define FOUT "lampa.out"
#define MAX_S 3100000
#define sz(x) ((int)(x).size())

int N, M; string A, B, C, S;
ifstream fin; ofstream fout;

void works(const char a[], const char b[])
{
    int i, p = 0, n = strlen(a), m = strlen(b);

    for (i = 0; i < sz(C); ++i)
        if (C[i] == 'A')
        {
            if (memcmp(S.c_str()+p, a, n)) return;
            p += n;
        } 
        else 
        {
            if (memcmp(S.c_str()+p, b, m)) return;
            p += m;
        }
    fout << a << endl << b << endl;
    exit(0);
}

int main(void)
{
    int i, j, a, b;

    fin.open(FIN, ios::in); 
    fout.open(FOUT, ios::out);

    fin >> N >> M >> S;

    A = "A"; B = "B";
    for (i = 3; i <= N; ++i)
    {
        C = A+B;
        A = B; B = C;
        if (i == N-2) a = sz(C);
        if (i == N-1) b = sz(C);
    }

    for (i = 1; i*a <= M; ++i)
    {
        j = M-i*a;
        if (j%b) continue;
        j /= b;
        A = N&1 ? S.substr(0, i) : S.substr(j, i);
        B = N&1 ? S.substr(i, j) : S.substr(0, j);
        works(A.c_str(), B.c_str());
    }
    fout << 0 << endl;

    return 0;
}