#include <bits/stdc++.h>

using namespace std;
 
#define DEBUG(x) cerr<<#x<<": "<<x<<endl;
#define DEBUG_VEC(v) cerr<<#v<<":";for(int i=0;i<v.size();i++) cerr<<" "<<v[i]; cerr<<endl;
#define DEBUG_MAT(v) cerr<<#v<<endl;for(int i=0;i<v.size();i++){for(int j=0;j<v[i].size();j++) {cerr<<v[i][j]<<" ";}cerr<<endl;}
typedef long long ll;
#define int ll
 
#define vi vector<int>
#define vl vector<ll>
#define vii vector< vector<int> >
#define vll vector< vector<ll> >
#define vs vector<string>
#define pii pair<int,int>
#define pis pair<int,string>
#define psi pair<string,int>
#define pll pair<ll,ll>
template<class S, class T> pair<S, T> operator+(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first + t.first, s.second + t.second); }
template<class S, class T> pair<S, T> operator-(const pair<S, T> &s, const pair<S, T> &t) { return pair<S, T>(s.first - t.first, s.second - t.second); }
template<class S, class T> ostream& operator<<(ostream& os, pair<S, T> p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
#define X first
#define Y second
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define rrep1(i,n) for(int i=(int)(n);i>0;i--)
#define REP(i,a,b) for(int i=a;i<b;i++)
#define in(x, a, b) (a <= x && x < b)
#define all(c) c.begin(),c.end()
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a = b; return 1; } return 0; }
#define UNIQUE(v) v.erase(std::unique(v.begin(), v.end()), v.end());
const ll inf = 1000000001;
const ll INF = (ll)1e18 + 1;
const long double pi = 3.1415926535897932384626433832795028841971L;
#define Sp(p) cout<<setprecision(25)<< fixed<<p<<endl;
// int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
// int dx2[8] = { 1,1,0,-1,-1,-1,0,1 }, dy2[8] = { 0,1,1,1,0,-1,-1,-1 };
vi dx = {1, 0, -1, 0}, dy = {0, 1, 0, -1};
// vi dx2 = { 1,1,0,-1,-1,-1,0,1 }, dy2 = { 0,1,1,1,0,-1,-1,-1 };
#define fio() cin.tie(0); ios::sync_with_stdio(false);
const ll MOD = 1000000007;
// const ll MOD = 998244353;
// #define mp make_pair
//#define endl '\n'


signed main() {
    ll n, k;
    cin >> n >> k;
    deque<int> deq;
    rep (i, n) {
        char c;
        cin >> c;
        deq.push_back(c - 'A');
    }

    if (n == 1) {
        if (k % 2 == 0) {
            cout << (char)('A' + deq[0]) << endl;
        }
        else {
            cout << (char)('A' + 1 - deq[0]) << endl;
        }
        return 0;
    }


    int cnt = 0;
    bool turn = true;
    while (k > 0) {
        if (cnt == 10000000) break;
        if (turn ^ (deq[0] != 0)) {
            deq[0] = 1 - deq[0];
        }
        else {
            deq.pop_front();
            turn = !turn;
            if (turn) deq.push_back(0);
            else deq.push_back(1);
        }
        cnt++;
        k--;
    }

    if (not turn) {
        rep (i, n) deq[i] = 1 - deq[i];
    }

    if (k == 0) {
        rep (i, n) {
            cout << (char)('A' + deq[i]);
        }
        cout << endl;
        return 0;
    }


    // DEBUG_VEC(deq);
    // DEBUG(k);

    int state;
    if (n % 2 == 0) {
        if (deq[0] == 1) state = 0;
        else state = 1;
    }
    else {
        if (deq[0] == 0) state = 0;
        else state = 1;
    }

    state = (state + k) % 2;
    string ans;
    rep (i, n) ans += 'A' + i % 2;
    reverse(all(ans));

    if (n % 2 == 1 and state == 1) {
        if (ans[0] == 'A') ans[0] = 'B';
        else ans[0] = 'A';
    }
    cout << ans << endl;
}


Measured memory_bytes: 5364